admin_view_work_orders_handler: remove unused import
admin_view_work_orders_handler: get_work_order_search_form() -> create_work_order_search_form()
WorkOrderSearchForm: restrict orgs to those from events available to the user
WorkOrderSearchForm: limit max per page to 250
WorkOrderSearchForm: change layout (heavy Bootstrap)
Bulk exporting: change sequence - fetch in the Abstract class
fabfile: check current branch - not always master
WorkOrderSearchForm: add more indexes
WorkOrderSearchForm: add spinner to Export Results button using Ladda
WorkOrderSearchForm: fix org lookups