CRM-14139 ajax grouplist call - fixes notices on non-static functions

----------------------------------------
* CRM-14139: Static methods called non-statically
  http://issues.civicrm.org/jira/browse/CRM-14139
Fix E-notice on AJAX getGroupList by returning empty array rather than null when no groups exist
test suite - fix signature on GroupCreate call
ACL Core, add a way for unit tests to flush in-function cache
Unit test on group selector AJAX call - add ability to return result for unit test
test fix Only variables should be assigned by reference

/var/www/drupal/sites/default/modules/civicrm/civicrm-core/CRM/ACL/BAO/ACL.php:541
Add function to set up an ACL for a test
GROUP ACLS add todo to indicate where function does not work correctly
Add GROUP ACL test - this test works except for the groupCount being wrong
CRM-14109 fix groupCount on no permission, note that removing the  if c
causes the access CiviCRM but no groups tests to start returning the same (incorrect) number of groups as the getCount does prior to this patch, adding the 0 =1 fixes both back again

----------------------------------------
* CRM-14109: Permissioned users being blocked from viewing disabled (but otherwise 'permissable' groups)
  http://issues.civicrm.org/jira/browse/CRM-14109