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
more general command-line handling (including ability to check version of psiturk you are using)
minor issue with the config file thing

this always creates a config.txt in the current directory if psiturk command is run.  this creates config files everywhere on your system if you are careful.  now just warns you and quits if psiturk can't find a config file.
patches bug where server host could not be set to anything except localhost

This is not a complete bugfix for this issue.  There are remaining problems if the server and dashboard are located on different computers.  However, this improves things.