Add LESS option to half_pipe:install rake task

- Add csso and less Gruntfile tasks
Add Less option reference to README
Update grunt-contrib-less version
Generate an initial main.less
Add sourceMap options to less task
Better text on README for processor option
Add bower_components directory in 'paths' less option
Merge remote-tracking branch 'gbmoretti/less-generator'
Add note about installing from Github for LESS support