resource: extend backend functionality for lua support and notification
resource: add 'dontwait' flag
resource: add resource.method.recalc(zone_name) function
resource: add mrp_zone_mask_t
resource: add mrp_resource_owner_recalc(zone) to resource manager interface
resource: add mrp_application_class_get_priority() to manager API
resource: deterministic event order: revokes/denies first followed by grants
resource-native: don't crash on 'premature' resource-set creation attempts.

Fail gracefully instead of crashing in the client library if a
client tries to create a resource set before it has received an
MRP_RES_CONNECTED event (ie. before the backend has been successfully
contacted and queried for resources).