Broken again...

- Help text moved to top of script for easy access
- Removed --install option; config now uses directory options instead
- lib_dir changed to install_dir, semantics changed slightly
- log name for uwsgi and dehr processes now configurable
- reordered task_uwsgi_emperor and task_uwsgi_vassal
- No longer using /tmp/dehr; now using /vagrant/tmp instead
- Pip package check broken somehow??? (Tests seem to return 127)
- Now using log files for uwsgi emperor and vassal processes
- Installer now restarts uwsgi on every change
- Sockets and pid files now stored in the var_dir rather than tmp_dir
- Fixed a broken check for download failure
- get_install_dir and get_var_dir deleted since no longer used