Conflicts:
	android/service/engine/AndroidManifest.xml - use file from 2.4
	modules/contrib/src/detection_based_tracker.cpp - move #include <pthread.h> as in 2.4
	modules/java/android_test/src/org/opencv/test/OpenCVTestRunner.java - use file from 2.4

- Adding Android SDK/ADT r21 compatibility;
- fixing stl headers path for new ndk;
- fixing native API level for Android projects

Libinfo revision formating fix;
HW dependent VersionCode for Manager implemented.

OpenCV testing via OpenCV Manager implemented.