Feature/password auth

"password" token generation takes your token, your username (full username), your password in plain text, and the desired "scopes" (privileges). and creates a temporary token with those privileges. 

The temporary token seems to live for the same amount of time as the access token you get from hipchat's website and the "personal" token generation (1 year). However, this token also comes with a refresh_token used to refresh the token with the refresh_token auth (not implemented yet).