* Expose more C++ functionality in the Java wrapper of the Mat class
In particular expose methods for handling Mat with more than 2 dimensions
* add constructors taking an array of dimension sizes
* add constructor taking an existing Mat and an array of Ranges
* add override of the create method taking an array of dimension sizes
* add overrides of the ones and zeros methods taking an array of dimension sizes
* add override of the submat method taking an array of ranges
* add overrides of put and get taking arrays of indices
* add wrapper for copySize method
* fix crash in the JNI wrapper of the reshape(int cn, int[] newshape) method
* add test for each method added to Mat.java

* Fix broken test

* fix android lint error in BaseLoaderCallback (LongLogTag)

Lint Error that was causde by the to long TAG:
BaseLoaderCallback.java:31:
Error: The logging tag can be at most 23 characters,
was 31 (OpenCVLoader/BaseLoaderCallback) [LongLogTag]
Log.e(TAG, "Package installation failed!");

* add requested "OCV" prefix for android logging

Lab/XYZ modes have been postponed (color_lab.cpp):
- need to split code for tables initialization and for pixels processing first
- no significant performance improvements for switching between SSE42 / AVX2 code generation

Currently the thresh is hard-coded to be 0.2 and nms_threshold as 0.4.

According to the gstreamer docs [1], the GstMessage pointer returned by
gst_bus_pop() is nullable, meaning NULL is a valid return value.

Previously, gst_is_missing_plugin_message would throw an assert when its
message object parameter would fail the GST_IS_MESSAGE macro check,
crashing the entire process (unless running in a try-catch block of course).

Instead of relying on valid messages, check if the message object itself is
valid before passing it to other gstreamer functions.

[1] https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstBus.html#gst-bus-popSigned-off-by: Christopher N. Hesse <raymanfx@gmail.com>

Must have that flag. Otherwise following "doxygen overview" tutorial won't work.