Split Contributing section from README.md into CONTRIBUTING.md

Signed-off-by: Steven Downer <grinch@outlook.com>
Merge branch 'master' of github.com:AlmuraDev/SpoutcraftMod
Add frame, fix clip issues in Container, frame use in test gui, license
on ActionEvent
Signed-off-by: Unknownloner <unknownloner.online@gmail.com>