Update Tilt 2.x
Add support for preferred extension to the resolver including resolver tests
Add template tests (extensions, mime types, etc.)
Add support for extension and mime type to template
Remove debugging code
Update Gemfile in test project
Add support for preferred extension in partials, a .json.erb will now prefer a .json.erb partial.

This fixes #20
Merge branch 'master' of github.com:DigitPaint/html_mockup