perspectiveTransform simplify assert() for better debuggin

When using perspectiveTransform in rather complicated settings, it would be easier for developers to have two separate assertions for each part of the boolean expression in order to pinpoint problems more efficiently. In my case I am struggling in Python2.7 with finding out whether scn+1 == m.cols or the depth == CV_32F || depth == CV_64F is making a problem, which is kind of hard.
Add AKAZE support for the Java wrapper
android: allow to build & run examples without Android OpenCV Manager
Merge pull request #2831 from alalek:android_examples
Merge pull request #2822 from timedia:akaze-java
Merge pull request #2817 from bf:patch-1