Update strings.xml

Added a comma.

use pgp key from contact if not set in muc
fixes #283

Merge branch 'android-auto-support' of https://github.com/morgenroth/Conversations into morgenroth-android-auto-support

Add content description to send button

Add reply button in wear design

The existing reply button for Android wear has been re-used from the action
bar. Instead of a 'send' icon, a 'reply' icon better matches the intended
action. Moreover, action icons for Android wear are solid white instead of
half transparent.

This can be used by screen readers and other accessibility aids.

fixes #2444

Apparently nimbuzz.com doesn't include status code 110 in muc self presence
It does however include the full real jid in the presence’s item.
We can use that as a work around to detect a self presence.

This patch adds required additions in order to show notifications
in Android Auto. Messages are read aloud and voice reply is
offered. The functionaliy has been tested with the Android Auto
standalone app as well as with the DHU simulator as describes
here:

https://developer.android.com/training/auto/testing/index.html

Removed unused imports from the entire project.

Minor code clean up