CRM-13863 - Get rid of double title for forms that use popups

Transfer responsibility for page title from tpl to php.
Add setPageTitle helper method to CRM_Core_Form.
And a bit of misc form/tpl cleanup
CRM_Contribute_Form - Cleanup code redundant with CRM_Admin_Form
Fix missing arg from fn declaration
Improve action-item style
Add pager to contact pledge tab
CRM-15147 - Fix bug where embedded search shows wrong content after paging and refreshing