Account avatars constructed from background and icon. One icon used for all avatars, background corresponds to account color.

Chat message balloons now have borders.

Conflicts:
	app/build.gradle
	app/src/main/java/com/xabber/android/ui/ChatViewer.java
	app/src/main/java/com/xabber/android/ui/helper/ContactTitleActionBarInflater.java

 Avatar inflater helpers removed.

ChatViewerFragment: context menu fixed.