add function determine absolute path to wiki.
add function to determine path of namespace

- In order to tackle the autochdir issue,
  we will need to determine the absolute
  filepath of a namespace.
use absolute instead of relative paths

- this solves the autochdir problem, because
  relative filepaths wouldn't work, if the
  context changes unexpectedly.
add haml and rdiscount dependency information.
bump the version to 0.9.5.