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

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

Fix crashes when no Bluetooth or no Camera is available

Briar crashed when run in a device without bluetooth or without camera
such as an emulator.

Closes #514

See merge request !269

Briar crashed when run in a device without bluetooth or without camera
such as an emulator.

Closes #514

Prevent empty state messages from showing briefly

When we clear a list in `onPause()`, the proper behavior is that the empty state
message is shown, because the list is indeed empty.

However, we will reload the list content again in `onResume()`,
so the fix chosen in this MR is to force showing the progress bar
right after clearing the list.

Closes #576

See merge request !267

Fix SharerLeavesBeforeResponse Integration Test

Closes #575

See merge request !266

Fixes #572, #578.

Fix regression where forum entries were not shown

Closes #565

See merge request !271

Closes #565

Closes #429

When we clear a list in onPause(), the proper behavior is that the empty state
message is shown, because the list is indeed empty.

However, we will reload the list content again in onResume(),
so the fix chosen in this commit is to force showing the progress bar
right after clearing the list.

Closes #576

UI for sharing blogs

Not posting any screenshots, because the UI is the same as for forums.

This does not yet offer the possibility to unsubscribe from blogs again. Should be done in a different MR as this one is big enough already.

Closes #498,  #497

See merge request !263

Closes #575

This refactors the current SharingStatusActivity
so it can be used for forums and blogs.

This refactors the forum invitation code,
so it can be used by both: forums and blogs.

This commit refactors the code for sharing forums,
so it can be used for sharing blogs as well.

It does not yet include code for responding to blog invitations.

Fix two Blog NPEs

Closes #571

See merge request !264

Closes #571

Simple UI for Managing and Importing RSS Feeds

Please note that this does not yet include the reblogging style for displaying imported RSS entries.

![device-2016-07-26-170732](/uploads/e7f53f72e955d0c37518e0d552121105/device-2016-07-26-170732.png)
![device-2016-07-26-170755](/uploads/b8e0c91ed496b618d330364e840458dc/device-2016-07-26-170755.png)
![device-2016-07-26-171519](/uploads/fae5c16255d5a67673a4bd9be73c165f/device-2016-07-26-171519.png)

Closes #517

See merge request !251

Post new RSS entries into the user's personal blog

Closes #486

See merge request !250