Improvements in issue forms
Added new comment form
Filter dashboard issues and project by user
Added project issues
Added status field to issue forms
Order dashboard issues by priority
Refactored ProjectRole to Participant and added Project functional tests
Fixed more code style issues
Minor improvements related with Behat and code-style

- Removed support for 5.3.3 because we are using traits
- Added Behat code-coverage extension (only for dev env)
- Added badges