* adds Material Request to `status_map`
* updates eval condition for Partially Ordered in Material Request map
* changes material_request doctype to include "pending", "ordered", "partially ordered", "issued", "transferred" as options
* adds more options to `validate_status`
* adds `set_status` just before saving
* adds `check_for_closed_status` in `before_cancel`
* adds patch to convert status to material request specific status
* adds stricter status update conditions
* changes `update_status` to me `set_status`
* adds checker such that draft status can only change to pending
* renames `check_draft_status` to `status_can_change`
* adds Cancelled to Material Request map
* makes `status_can_change` block any attempt to change a cancelled document
* adds more test cases
* updates what `set_status` checks for before adding comment
* adds patch to rename the present material request status