Add Unit tests for CryptoComponent#hash()

See merge request !464

Move all unit tests to their modules and remove briar-tests

There are now tests in these modules:
* bramble-api
* bramble-core
* bramble-j2se
* briar-core
* briar-android

In order to run all -core tests together, the following AS run configuration can be used:
![Screenshot_2016-12-12_16-37-53](/uploads/8c706406f015ecd9e2371ebc28e6b34c/Screenshot_2016-12-12_16-37-53.png)

Closes #778

See merge request !456

Add sharing information to private group ActionBar subtitle

![device-2016-12-12-114533](/uploads/b31fc37643ef6e817a80a4ddd767fe98/device-2016-12-12-114533.png)

Closes #646

See merge request !455

Make notification icon less similar to superuser icon

Closes #155

See merge request !458

Add creator and online information to group member list

![device-2016-12-06-102258](/uploads/90e19a6ca31aaf91c6ebf3ea8e218b3f/device-2016-12-06-102258.png)
![device-2016-12-06-110113](/uploads/3fd62f7cdfe75419a07262356d27b952/device-2016-12-06-110113.png)

Closes #813

See merge request !448

Move integration tests to their proper packages

Closes #777

See merge request !453

Make animations more consistent

![animations6](/uploads/0ac694d3561515e04fbb9032d31f183c/animations6.mp4)

Closes #570, #621

See merge request !439

This also removes the BriarFragmentActivity that was only really used by
the NavDrawerActivity.

Add sharing info to ForumActivity action bar subtitle

This indirectly does also most of the work for adding the same information to private groups. However, completing this is blocked by !448.

![device-2016-12-07-152915](/uploads/5bb42f2e78a87931b0307e7597ba72c5/device-2016-12-07-152915.png)

Second part of #646

See merge request !451

Add blog sharing information to toolbar subtitle

This MR introduces a new `SharingController` which is supposed to be used in activities that show blogs, groups and forums. Feedback on this approach is welcome before this is used to add "Shared with" support to other parts of the UI.

The toolbar subtitle shows information about how many contacts the current shareable is shared with and how many of those are online.

So far this is implemented for blogs:

![device-2016-12-05-180207](/uploads/13afb4c7c5d10ad29c414865ee02670d/device-2016-12-05-180207.png)

One part of #646

See merge request !447

Add unit tests for PeerProtocolEngine

Although not all classes have unit tests, this

Closes #766

See merge request !450

Add unit tests for InviteeProtocolEngine

Next part of #766

See merge request !444

The toolbar subtitle shows information about how many contacts the
current blog is shared with and how many of those are online.

Fix Sharing Status screens

* Remove distinction between "shared with" and "shared by"
* Show all contacts a blog is shared with
* Show online status of contacts in sharing screen

![device-2016-12-05-142949](/uploads/703fbd2d52815374e57edd89f754bf6c/device-2016-12-05-142949.png)

Closes #810

See merge request !445

Remove verbose logging from introduction client

Closes #808

See merge request !449

Introduce Dialog Theme for Onboarding

Currently onboarding dialogs and confirmation dialogs look the same. This MR introduces a new dialog theme for onboarding dialogs that looks like the tap target onboarding, so that the user can immediately spot the purpose of the dialog.

![device-2016-12-06-085539](/uploads/6d75b17c0f20028bb7ffac65e6fba03a/device-2016-12-06-085539.png)

See merge request !446

* Remove distinction between "shared with" and "shared by"
* Show all contacts a blog is shared with
* Show online status of contacts in sharing screen

Require a label for hashing

* Add a string label argument to `CryptoComponent#hash()`
* Convert `DoubleDigest` from implementing `MessageDigest`
  to implementing `org.spongycastle.crypto.Digest`
  (we need to keep `DoubleDigest` for `FortunaGenerator`)
* Convert all other uses of `MessageDigest` to `CryptoComponent#hash()`
* Remove `CryptoComponent#getMessageDigest()`, `MessageDigest` and `DigestWrapper`

Closes #548

See merge request !442