This also adds a setting allowing people to turn blog post notifications off.

Closes #488

Closes #415

The forum UI depended on sync layer events such as MessageStateChangedEvent.
Now, the forum client broadcasts its own high-level event (`ForumPostReceivedEvent`)
with the information the UI needs (`ForumPostHeader`).

Closes #310

This prevents trying to access the same group metadata in different groups.
Also, the conversation does not need to be reloaded once introduction messages arrive.

Closes #535

Closes #533

This simple fix contributed by @m8r-v9bo74 fixed the issue on my Xperia
Pro that could never focus on the QR code before. Focusing and scanning
still works on my other test devices.

Closes #346

* Explain what "account creation" means on first run
* Use hints instead of dedicated text views
* Move password strength meter up into the user's view
* Always move user's view to current input field
* Improve "Forgot Password" dialog

Closes #151

to make it clearer who will be introduced.

Closes #360

Closes #452

Closes #455

This commit addes a combined blog feed that shows all posts of all
subscribed blogs in the order the blog posts have been received.

For now, this commit also hides other blog functionality like adding
additional blogs and browsing individual blogs.

Closes #417

Closes #418

This allows for swiping left/right to read other posts by using
a ViewPager.

This hasn't been done as a separate activity, but with
fragments, so both can share the `BlogPersistentData` without
needing to reload it.

Closes #428

Closes #411

This commit lays the groundwork for #415

This does not yet support multiple identities. It just shows blogs
created by the first identity, but can easily be adapted for
multi-identity support.

Closes #410

Clicking the plus in the toolbar open the `CreateBlogActivity` which
allows the user to create a new blog. Only the first identity is
considered, but support for more identities can be easily added later.

The actual list of blogs in the My Blogs tab will be done in the next
commit.

This implements very basic and simple empty state messages for the
current features.

Closes #327

Closes #397

Closes #326

Closes #442