bug fixes and tiny functions added

1. die if mysql_select_db fails
2. fix url error when the app is under root domain
3. fix limit -1 error of mysql query
4. fix include_once return true instead array when getting the widget
configuration
5. add dataTables API in file and db pager module
6. add awk 'IN' condition in file pager module
7. fix bugs in ajaxform widget, add trigger API to trigger a form into
ajaxform anytime using js and tip direction configuration