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.

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

Also prevents the snackbar from hiding the bottom of the list.

Closes #337