add buildout

Buildout changes:
 - move default_settings.py into templates/settings.py, which is updated with build-time params into src/mpyc/settings.py
 - move code into src/
 - create setup.py
 - add bootstrap.py
 - add buildout.cfg


to build:
 - checkout
 - `python bootstrap.py -d`
 - bin/buildout

this creates cmds in bin/ running in a virtualenv 

to run:
 - bin/run_server