change markdown engine to rdiscount

People say that it has better chinese support.
Hope it is true :P

please install needed library

    $ sudo gem install rdiscount
doc: add how to use irc

source from dev.g0v.tw
doc: add how to use issue tracker

authored by billy3321
doc: add how to use wiki

authored by billy3321
doc: update join page
doc: update works.md

To append more description of projects.
this page needs more love to make it complete.