Added implementation for RGB to YUV420p color conversion
Added tests for RGB to YUV420p color conversion
Added multithreaded implementation for RGB to YUV420p color conversion
Merge pull request #491 from Daniil-Osokin:cvtRGB2YUV420p
moving JNI library to 'build/lib' dir on non-Win
updating JNI lib location for Unix; formatting update
more formatting
minor formatting
removing redundant code
Merge pull request #620 from apavlenko:java_tutorial_fix