Unused drawable resources (accounts panel background and icon) removed.

Work for https://github.com/redsolution/xabber-android/issues/330

Based on this commit:
https://github.com/languitar/xabber-android/commit/d6ef6a43b4386d621311e752b7c3f0a310576d2d

ChatViewer: chats completely updated only then needed. Better performance and incoming message animation restored.

InfiniteViewPager not used anymore.

Merge branch 'inband-registration' of https://github.com/aelmahmoudy/xabber-android into aelmahmoudy-inband-registration

A kind of solution of ViewPages hangs up: ChatViewerAdapter count set to 200, InfiniteViewPager offset set to 100.

Unstable, could hang up on chat select.

antonyt/InfiniteViewPager used partially.