[STUMP] Module changes (no more contrib-dir!)

Hi All,

The latest git commit does to user-visible changes:
contrib-dir -> module-dir (and all functions/variables)
The module-dir now defaults to:
~/.stumpwm.d/modules

You can "install" modules with:
make install-modules

This just clones the stumpwm-contrib directory to ~/.stumpwm.d/modules.

If you call (set-contrib-dir "foo"), it should pop up a message telling
you to prefer add-to-load-path instead.  

If there are no bugs introduced by this commit, and I can address the
NumLock bug, I'll be releasing 0.9.9 very soon.

    Dave