When a specific TimeEntryActivity are change, associated TimeEntries will be re-assigned to the correct record. * Renamed build to create since the methods now create objects. * Removed call to Project#save that isn't needed since objects are saved directly now. * Wrapped the activity creation and updates in a SQL transaction so TimeEntries will remain in a consistent state if there is an error. * When a Project's TimeEntryActivities are destroyed, they are now reassigned to the parent TimeEntryActivity. #4077 git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@2950 e93f8b46-1217-0410-a6f0-8f06a7374b81