e.g. <opencv2/core/core.hpp> become <opencv2/core.hpp>

Also renamed <opencv2/core/opengl_interop.hpp> to <opencv2/core/opengl.hpp>

Common part of all source files is extracted to special header

More granular build of Java API: it is now possible to build Java wrappers only for the subset of OpenCV modules

* fixed manually ported classes;
* added vector<vector<Point>> support;
* changed argument types for 3 functions;
* finished tests for org.opencv.core.Core class.