To edit the TPS configuration, do not edit config.json.in in the tree. 
Instead, edit config.json inside your virtualenv; it will be located at
something like:

  (linux): /path/to/virtualenv/lib/python2.6/site-packages/tps-0.2.40-py2.6.egg/tps/config.json
  (win): /path/to/virtualenv/Lib/site-packages/tps-0.2.40-py2.6.egg/tps/config.json