removed directories
updated modules
updated grunt plugins
improved code
changed src path
changed to use styl extension only
added assets directory
some changes to Gruntfile.coffee

- appended compile task
  - it similar to rebuild task, but not remove to public/lib
- changed rebuild task
  - appended execute bower task
fixed sourceMapURL
fixed unit test
some changes to README.md

- appended compile section
- appended watch file list to develop section
- changed description of install section
appended changes to HISTORY.md