and maintain keyboard state when hiding view.

This commit also moves various blog classes into their own packages and
makes the required visibility changes.

All text that can be generated by users will show emoji from the
shipped sprites.

For all messages and posts, the custom emoji keyboard is now available.

This also disables menu actions rather than hiding them and thus
closes #677

Included is a fix for a regression that was not showing the keyboard
automatically in forums and thus
closes #676

Add functionality to save and restore recently used Emojis

Update emoji and add new categories based on AOSP's XML file

by making it only selectable in detail view

This also adds comments to the blog post detail screen that were
previously missing.

Also replace more raster graphics with vector graphics.

Closes #342

No more general disabling of abortOnError
Resolved all *errors* beside language ones  MissingTranslation & ImpliedQuantity
Issue context: #567

Closes #429

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.

Closes #517