CAS-1398: Added contributing.md file

Also modified travis build to check for commit messages based on guidelines
CAS-1398: Added contributing.md file

Also modified travis build to check for commit messages based on guidelines
CAS-1398: Added contributing.md file

Also modified travis build to check for commit messages based on guidelines
CAS-1398: Added more keywords to commit messages
Merge pull request #409 from Unicon/CAS-1398

CAS-1398: Adding a contributing.md file