Fixes #4476: Static files are now recognized as views
Converts Trac info to markdown
Unifies our disparate contribution guides.
Merge pull request #5070 from ewinslow/contributing

Adds CONTRIBUTING.md
Merge pull request #532 from ewinslow/support-static-views-b4476

Fixes #4476: Static files are now recognized as views
Fixes #4420: Allow multiple user pickers, new features, AMD refactoring