update quickstart and formatting.
gunicorn's import_app will search the correct path for the experiment.py application.  fixes #47
simplifying a bit, caught some typos
Update README.md

fix install link in quickstart
Merge commit '69f5ca907b16806533663f3f95cecaec0af46caf'

# By Jessica B. Hamrick
# Via Jessica B. Hamrick
* commit '69f5ca907b16806533663f3f95cecaec0af46caf':
  Add dashboard parameters to enable dashboard authentication
adding citation information
creates config.txt when psiturk-setup-example is run

otherwise users might be confused when file doesn't exist.  config.txt files should be includes with experiment archives i think minus database/password info
amazon has changed link to access/manage your keys
Update README.md
Add option to disable launching the browser when starting psiturk