added travis build status image to readme
removed unused function union()
added a licence file
Merge branch 'master' of github.com:ngn/u into grunt-build
WIP - fixed some issues

 1. Fixed travis config for grunt
 2. Removed accidentally committe compiled js files.
 3. Added wrapper build script
 4. Updated the toplevel .gitignore
 5. grunt.coffee is the build configuration file now