Add build/ and installed-files.txt to .gitignore list.
Add support for tordyguards config file with configparse.

 * REMOVE src/settings.py.
 * ADD tordyguards.conf, which is installed to
   /etc/tordyguards/tordyguards.conf.
 * ADD support for parsing config files with configparse module.
 * ADD a bit of documentation.
 * MOVE src/wicd_tor_change_state.py to bin/tordyguards.py, because it's
   more meant to be a script, and isn't really part of a module
   library. A commented out `scripts=[]` setuptools directive has been
   placed in setup.py for later use when tordyguards is more
   modularised.
 * UPDATE TODO.md file to remove some of the config related tasks.
Bump version to 0.2.