Added contributing guide

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Add submodule

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Files, encoding and much more

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>