Set allow_on_submit for 'page_break', 'letter_head', 'select_print_heading', 'print_heading'. Fixes frappe/erpnext#1810
Merge pull request #2167 from anandpdoshi/anand-september-9

Set allow_on_submit for 'page_break', 'letter_head', 'select_print_heading', 'print_heading'. Fixes frappe/erpnext#1810