Adds first translations to source code and sets up transifex config
file. Pull more translations later with:

 cd briar-android
 tx pull --mode=developer

Closes #448

Backend for Automatic Micro Blogs

This MR introduces automatic personal blogs to the Blog client. When a contact is added, her personal blog will also be added automatically. Also, when a new identity is added, a personal blog for that identity is created.

The first commit changes the blog paradigm to short-form blogs and introduces other things that will be useful later in the UI (!214) such as a BlogPostAdded event and the possibility to delete/remove blogs (not the personal ones).

This MR is based on !224 to prevent crashes that are fixed by it. So please review and merge !224 first.

See merge request !223

This is useful when sorting blog posts in the combined feed. It ensures
you do not miss older posts that were just synced to you.

When a contact is added, her personal blog will also be added automatically.
Also, when a new identity is added, a personal blog for that identity is created.

Part of #436

Removes teaser and makes body mandatory.

It also adds support for deleting blogs and
introduces a getAuthorStatus() method to the IdentityManager
that takes a running transaction.

Remove MAX_GROUP_DESCRIPTOR_LENGTH

Closes #441

See merge request !224

Closes #441

Forum improvements

Forum Activity improvements:

* Orientation changes now restore the activity properly, e.g. input text and state is retained
* Snack bar is now, when appropriate, clickable
* The bottom divider is no longer visible for the bottom entry
* Code refactoring for improved simplicity and less redundancy
* Timestamp check to ensure that new posts are not older than the latest post

Closes #426 
Closes #423 
Closes #424 

See merge request !218

Fixing fragment instance restore

Alas, it turns out that my neat way of integrating the Fragments into the dependency graph was not without problems. Me and @grote discovered that this presented us with a lot of problems on orientation changes as the Activity is re-created, and therefore parts of the dependency graph. The simplest solution was simply to abandon the idea, i.e. with this branch Fragments are no longer part of the dependency graph. 

See merge request !215

synched conversation and forum input

Closes #354

See merge request !219

Implement Blog Sharing Client

Closes #403

See merge request !220

Fix test broken by #78



See merge request !221

Blog Client with Factories and Validator

This implements a simple initial blog client that covers the basic blog actions, but no deletion/removal of blogs, yet.

Classes for Blogs and Blog Post Headers have been introduced along with the associated factories.

A `BlogPostValidator` has been added that validates incoming blog posts.

Closes #402
Closes #404

See merge request !212

New Trust Level Indicator Replaces The Stars

This implements a generic `TrustIndicatorView` with a `setTrustLevel()`
method which updates the drawable according to the `Author.State`.

It also removes unused files from the repo.

This is based on !212 and should only be merged after it.

Closes #78

See merge request !217

This implements a generic `TrustIndicatorView` with a `setTrustLevel()`
method which updates the drawable according to the `Author.State`.

Closes #78

This implements a simple initial blog client that covers the basic blog
actions, but no deletion/removal of blogs, yet.

Classes for Blogs and Blog Post Headers have been introduced along with
the associated factories.

A `BlogPostValidator` has been added that validates incoming blog posts.

Closes #402
Closes #404

fix persistance

Closes #433

See merge request !216

Add a UI for changing the password

Closes #390

See merge request !213

Fix NPE in ForumSharingStatusActivity by only accessing group in contact list

Only access group in contact list where it is guaranteed to exist.

Closes #430

See merge request !211

by checking if a group ID exists.

Closes #430

Client layer events for messaging

Adds and uses a new `PrivateMessageReceivedEvent` and eliminate the need for an event for adding local messages. Both done in separate commits.

This addresses part of #309

See merge request !208

Address Race-Condition in Forum Sharing

When Two Contacts Share Same Forum with each other at the same time a race condition causes them both to delete each other's invitation. This is solved by an Alice/Bob test as suggested in #388.

See merge request !205

Adds badges to the forum list that indicate unread posts

This MR adds  badges to the forum list that indicate unread posts. It does so by extending the compound view `TextAvatarView` and provides convenient setters that take care of the required UI changes. The new badge can also be used to indicate a problem with the forum.

![device-2016-06-02-134048](/uploads/133f365f5654be304f590a4f5b667d06/device-2016-06-02-134048.png)![device-2016-06-02-134453](/uploads/423a88f6306a558828181f0c539aa1cb/device-2016-06-02-134453.png)

I decided not to check if the forum is shared from someone or with someone and indicate a problem in this case, because this requires iterating two times over all contacts and their group metadata for each forum. If someone considers it important to check for this information, we can create a ticket for doing this within the forum and not in the forum list.

See merge request !207

Blog Fragment in Navigation Drawer with Tabs

This replaces the custom layouts in the navigation drawer with a
`NavigationView` and adds a menu entry for Blogs.

A Main Blogs fragment is added that holds a `TabLayout` and a
`ViewPager`. Five tabs are already added, but they just have a single
placeholder fragment that is to be replaced by the actual fragments.

Please note that the header in the navigation drawer is just provisional. I am sure @Megalox can design a better one.

![device-2016-06-02-191101](/uploads/ddffee792f67fad01158d7adc7ca904d/device-2016-06-02-191101.png)
![device-2016-06-02-191048](/uploads/a5e6def118646a02c6bcbf17e0398484/device-2016-06-02-191048.png)

Closes #409

See merge request !210

This replaces the custom layouts in the navigation drawer with a
`NavigationView` and adds a menu entry for Blogs.

A Main Blogs fragment is added that holds a `TabLayout` and a
`ViewPager`. Five tabs are already added, but they just have a single
placeholder fragment that is to be replaced by the actual fragments.

Closes #409

It does so by extending the compound view `TextAvatarView` and provides
convienient setters that take care of the required UI changes.
The new badge can also be used to indicate a problem with the forum.

Closes #408

with each other at the same time.

Closes #388

fixed sub-tree duplicate bug

Closes #422

See merge request !206