rest API: no more key needed

Hi,

Two changes to make it easier:

1) Now you don't need a key. As soon as you are authenticated, you can run (example)

http://example.com/sites/all/modules/civicrm/extern/rest.php?q=civicrm/contact/search
or with more param (only the individuals, and return the name, mail and country)
http://example.com/sites/all/modules/civicrm/extern/rest.php?q=civicrm/contact/search&contactType=Individual&return[email]=1&return[sort_name]=1&return[country]=1

on every case you can have it as a json format:
http://example.com/sites/all/modules/civicrm/extern/rest.php?q=civicrm/contact/search&json=1

2) Now the authentication returns the session ID

http://example.com/sites/all/modules/civicrm/extern/rest.php?q=civicrm/login&user=xx&pwd=yy
returns a PHPSESSID that you can uses as a get param on the other queries

eg:
http://example.com/sites/all/modules/civicrm/extern/rest.php?q=civicrm/contact/search&PHPSESSID=a956745e3d0056377adaa63a1c9dbb95