add more infos to --help binary flag

Output :

    $ ./bin/blessc --help                                                                                                                                                       
    Usage: blessc [options] [ source | - ] [destination]
    
    Options :
      -v, --version      print version
      -h, --help         print this help
      -f, --force        overwrite input file
      -x, --compress     "minify" @import
      --no-cleanup       don't remove old css file before overwriting
      --no-imports       disable @import on stylesheets
      --no-cache-buster  turn off the cache buster
    
    Full documentation can be found at http://blesscss.com/