[STUMP] New asdf-loaded modules

Hi All,

After a weekend of fervent hacking, I'm happy to announce that I've
cobbled together enough functionality for adventurous hackers to play
with. 

This branch breaks *contrib-dir* and (load "/path/to/contrib/blah.lisp")
calls in your .stumpwmrc! To test this (assuming you've already setup
and built stumpwm with *contrib-dir* set to /path/to/stumpwm/contrib):
git pull 
git checkout load-module 
git clone [email protected]:stumpwm/stumpwm-contrib.git contrib 
make

(load-module "module-name") should work as before. 

Important notes: The actual call is (asdf:operate 'asdf:load-op
"module-name") which means that the content of *load-path* is
superfluous to actually compiling and loading the code.  *load-path* is
used to list available modules as well as check if a module exists.  The
variable that asdf is aware of asdf:*central-registry*, so if the module
is in your load-path but not in the central-registry you won't be able
to load the code without error. 

There are more notes in the commit log on github.

Happy Hacking,

    Dave