Add hidden service address for dev reports

Closes #573

See merge request !289

Server-side code for accepting crash reports and feedback

* Moved some shared code for copying InputStreams to OutputStreams into a utility class
* Modified the  dev report sender to send one report per connection
  * Easier to handle on the server side
  * If the connection fails after sending any reports, they don't need to be resent
  * Tor will reuse the circuit, so it's cheap
* Added server-side code for accepting dev reports
  * We need to protect the server's resources from DoS attacks
  * Reports can't be larger than 1 MB
  * Connections are limited to an average rate of one per minute
  * The rate limiter uses a token bucket to allow bursts of up to 1,000 connections
  * If the rate limit is exceeded, connection attempts will fail - clients will retry next time they sign in
  * The limits can be raised when we move to a bigger server (and when we have some users)


See merge request !288

Stop supporting Gingerbread

Closes #566

See merge request !278

This allows simpler server-side code, and a failure part-way through sending won't require restarting from the beginning next time.

Fix two crashes when scanning QR codes

One crash was two due the `Context` being `null` and the other due to the camera being opened within an `AsyncTask`.

Closes #583

See merge request !282

Add introduced contacts as UNVERIFIED

This MR **breaks** the database schema requiring you to create a new account.

Closes #580

See merge request !280

Also, don't support unverifying contacts.

Closes #580

Validate New Messages for Reblogging and Comments of Blog Posts

Closes #591

See merge request !279

Also includes unit tests for the new message types.

Closes #591

Let clients decide whether to share messages or not

Before this MR, the `ValidationManager` was sharing all messages after they had been delivered. Now, it is within the client's responsibility whether to share messages or not. So far, only the Blog and the Forum client are sharing incoming messages.

Closes #595

See merge request !283

Group strings and remove unused resources

Before I grouped the strings, I removed unused resources as well to not group things that are not being used anymore.

The grouping tries to follow a normal usage lifecycle of the app where the user works their way down the navigation drawer and explores all features in one area.

Closes #342

See merge request !277

Also properly handle back navigation when trying to add contacts.

Don't try to reuse already bound ports for key agreement

This is one cause of #447, but probably not the only one.

See merge request !281

Don't crash when pressing Up button in WriteBlogPostActivity

Closes #587

See merge request !275

Closes #342

Closes #587

Update Tor assets if they're older than the APK

Extract the Tor binary, GeoIP database and config file from the APK if they haven't been extracted since the APK was last updated.

On the Galaxy Nexus, skipping extraction of the binary if it's already up to date shaves about 1.5 seconds off the Tor plugin's startup time.

Closes #582.

Depends on !272.

See merge request !273

Care for lint errors

No more general disabling of abortOnError
Resolved all *errors* beside language ones  MissingTranslation & ImpliedQuantity
Issue context: #567

See merge request !274

Don't connect to Tor if it's already running

For some time now we've had a reliable way of shutting down the Tor process (the __OwningControllerProcess command line argument combined with the TAKEOWNERSHIP command), but TorPlugin#start() still assumes that Tor may already be running. This allows another app to bind the Tor control and SOCKS ports and collect confidential data from Briar (#578). It also allows two Briar instances running on the same device to try to communicate with the same Tor process, which prevents proper shutdown (#572).

This patch prevents the Tor plugin from starting unless it's able to start its own Tor process with the expected control and SOCKS ports. If two Briar instances are running on the same device, only one of them will be able to use Tor. The other should fail to start its Tor plugin and then function normally without Tor access, including normal shutdown.

Fixes #572, #578. Open another ticket if you want two Briar instances on the same device to have their own Tor processes. :-)

See merge request !272

No more general disabling of abortOnError
Resolved all *errors* beside language ones  MissingTranslation & ImpliedQuantity
Issue context: #567

Allow unsubscribing from shared blogs

Only personal blogs from non-contacts can be removed.
This also adds integration tests that check the conditions under which blogs can actually be removed.

Closes #579

See merge request !268

Only personal blogs from non-contacts can be removed.
This also adds integration tests that check if blogs can actually be removed.

Closes #579

Return proper Invitation objects in SharingManager

Fixes #470

See merge request !265

Fixes #470

Show Explanatory Graphic Before Scanning QR Codes

![device-2016-08-04-182045](/uploads/9d6a5fea975d55e86dfe6d9bdbacb51c/device-2016-08-04-182045.png)
![device-2016-08-04-182058](/uploads/3ce86635f37ce2b903144a842d814d15/device-2016-08-04-182058.png)

Closes #429

See merge request !270