Usage of imread(): magic number 0, unchecked result
* docs: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* samples, apps: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* tests: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* doc/py_tutorials: check imread() result
* 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
