big refactoring of almost everything:
  common.py    - added list_dirs helper function
  nginx.py     - refactored to deal with change to apps handling
  provision.py - moved sudo privs assignment above everything else
                 to reduce the number of times a password prompt
                 is needed
  apps.py      - made each app a subdirectory and moved each app's
                 config file out of fabric.cfg and into a named
                 config file.  Also made the git repo mandatory
                 and started to add the code that will allow the
                 app configuration to be driven directly from
                 package.json