Moved isLinkNameFormatValid function out of id_user module to new common module. This function is going to be used by other form validation functions that require to validate linkname (different kind of Groups, Programs etc). Patch by: Pawel Solyga Review by: to-be-reviewed

A list of bugs is available in the Google App Engine SDK project on Google Code.

Please visit http://code.google.com/p/googleappengine for more details.