add a new function abssum
fix the bug of test and perf because someone remove non-free module from cmakelist.txt

Rair hangs on library installation fixed.

made it to give more verbose errors when arguments of wrong types are passed, added setters with types (e.g. setInt, etc)

Frame format setter added to both views.

Old Android support added;
Android 4.1.x fixes added;
Thead sync added;
Camera errors handling added.

Nexus 7 support added.

OpenCV initialization moved to onResume event to support package installation waiting.

Warnings fixed;
Nexus 7 support added to manifest.