Memory leak in color-blob-detection sample fixed;
Default face size in face-detection is set to 20%;
Error handling improved;
Some possible mat leak fixed;
Manager verison and engine interface version incremented to fix incompatibilities;
Docs updated;

Some unification done to simplify camera switching.

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.

This reverts commit eb4ce67d.

Conflicts:
	samples/android/color-blob-detection/src/org/opencv/samples/colorblobdetect/ColorBlobDetectionView.java

(cherry picked from commit 067744d0)

(cherry picked from commit fc935184)
Signed-off-by: Andrey Kamaev <andrey.kamaev@itseez.com>

(cherry picked from commit bd12f636)
Signed-off-by: Andrey Kamaev <andrey.kamaev@itseez.com>

(cherry picked from commit cd59cf3a)
Signed-off-by: Andrey Kamaev <andrey.kamaev@itseez.com>