Update CONTRIBUTING.md

Added contribution license
Update CONTRIBUTING.md

oops, did not mean to do this in master.
bump version to v1.3.1.0dev
Merge pull request #208 from boegel/v1.3.0.x

bump version to v1.3.1.0dev
Merge branch 'v1.3.0.x' into develop

Conflicts:
	setup.py