UI for reblogging and blog comments

This MR wraps all blog posts inside a `CardView` and adds a reblog button to blog posts. When this button is pressed, a new activity opens that shows the blog post again and allows the user to reblog it into their own blog. An optional comment can be added.

Also a new compound view `AuthorView` is introduced to display authors and their trust level in a consistent way.

The `BlogController` has been refactored, so the `FeedController` can share most code through an abstract base class.

![reblog2](/uploads/ce4764851c4cbe39684c95a3b427e3a2/reblog2.gif)

Closes #496, #437 

See merge request !300

Closes #593

Merge branch '605-add-database-method-for-retrieving-a-contact-by-local-and-remote-author-ids' into 'master'

Add database method for retrieving a contact by local and remote author IDs

Closes #605

See merge request !302

Scroll down Adding Contact screen

Normally, you would introduce a new layout only for small screens, but in this case it is easier and has less maintenance overhead to just scroll down the screen, so the button is always visible after loading.

While I was at it, I also replaced `getLocalAuthors()` by the new `getLocalAuthor()`.

Closes #616

See merge request !294

and use it for retreiving the status of an author faster.
Also add tests for both.

Closes #616

Factor out Tor Socks Port

This MR factors out the local Tor port, so other clients can listen to an `TransportEnabledEvent` for Tor and start tasks as soon as Tor becomes available. This would also enable client to pass traffic through Tor's local SOCKS proxy.

See merge request !301

Attach optional messages to invitations in Conversation view

![device-2016-08-29-115823](/uploads/e819324046b8a37ff06da7300046369c/device-2016-08-29-115823.png)![device-2016-08-29-115834](/uploads/051b4b64938bfa6f3ed610db28909865/device-2016-08-29-115834.png)

Closes #359

See merge request !299

Improve conversation screen graphics with less padding

This is how the conversation screen looks with this MR:

![1](https://code.briarproject.org/akwizgran/briar/uploads/3078636c93f7edc6b07034ad808ffc7c/device-2016-08-26-105325.png)
![2](https://code.briarproject.org/akwizgran/briar/uploads/fe0dcd3b1cbc6593aabed6faab1801d7/device-2016-08-26-105425.png)

This MR also replaces more raster graphics with vector graphics.

Closes #352

See merge request !298

Add support for comments and reblogging to Blog Client

Comments and reblogs need to depend on the post they refer to.
Since message dependencies are limited to one group,
the post and also the comments need to be wrapped
when commented on or reblogged to another blog (and group).

For this reason, in addition to comments, two new wrapping message types
are introduced. They retain all data of the original messages and allow
for reconstruction and signature verification.

This MR breaks backwards compatibility with old blog posts.
It removes the content type, title and parent ID from the post.

Furthermore, it includes one commit that replaces the `Message` in `MessageSharedEvent` with a `MessageId`.

Closes #494

See merge request !285

Sign Introduction Information to be able to discover MITM attack

The local introducee doesn't know whether each piece of information received from the introducer originates from the remote introducee or has been replaced by the introducer, i.e. whether the introducer is carrying out a man-in-the-middle attack.

The introduction protocol doesn't aim to detect or prevent man-in-the-middle attacks. We only aim to establish that if the remote identity public key is not replaced then the remote ephemeral public key, transport properties and timestamp are not replaced either. This MR adds a MAC and a signature to the introduction protocol's ACK message to fulfill that aim. See #364 for the detailed security argument.

Later, when the local introducee verifies that the remote identity public key belongs to a particular person (#513), she can also be sure that the remote ephemeral public key, transport properties and timestamp originated from that person.

Closes #364

See merge request !297

Before the introducee sends her ACK,
she derives a master key from the ephemeral shared secret as before.

Two nonces and a MAC key are then derived from the master key.
The local introducee signs one of the nonces and calculates a MAC
over her own identity public key, ephemeral public key,
transport properties and timestamp.
The local introducee includes the signature and MAC in her ACK.

On receiving the remote introducee's ACK,
the local introducee verifies the signature and MAC.
Should the verification fail, an ABORT is sent to the introducer and
the remote introducee that was added as inactive is deleted again.

The MAC and signature are not yet generated and verified.
This will happen in a later commit.

Comments and reblogs need to depend on the post they refer to.
Since message dependencies are limited to one group,
the post and also the comments need to be wrapped
when commented on or reblogged to another blog.

For this reason, in addition to comments, two new wrapping message types
are introduced. They retain all data of the original messages and allow
for reconstruction and signature verification.

This commit breaks backwards compatibility with old blog posts.
It removes the content type, title and parent ID from the post
message structure.

Fix various notification bugs

Fixes #539, #564, #568.

Depends on !276.

See merge request !286

Also replace more raster graphics with vector graphics.

Add MAC function to crypto component



See merge request !295

Define iteration order of BdfDictionary

Closes #618

See merge request !296

Use Briar's IoUtils.copy(), not H2's IOUtils.copy()

Our implementation closes both streams, H2's implementation leaves them open.

Closes #614.

See merge request !293

Blog controller thread safety

This patch removes the mutable list of posts from the blog controller to make it thread-safe, and adds a cache of message bodies to speed up reloads.

Closes #555.

See merge request !276

Cleanup Gradle and Proguard to fix connectedCheck

Closes #597

See merge request !284

Merge branch '311-audit-crash-report-and-feedback-fields-for-sensitive-or-identifying-information' into 'master'

Remove sensitive information from crash and feedback reports

This depends on MR !290 and removes also the crash report settings.

Closes #311

See merge request !291

Scrub addresses before logging them

MAC, IP and onion addresses are now scrubbed before logging to ensure we don't leave any sensitive information in plaintext on the device or send it in crash reports or feedback.

* Bluetooth MAC addresses keep the first and last octets
* IPv4 addresses keep the first and last octets
* IPv6 addresses should be scrubbed completely (couldn't test)
* Onion addresses keep the first three characters

If an address is invalid it will not be scrubbed to enable debugging, because it is most likely not sensitive.

Closes #592

See merge request !290

Closes #311