PLD: refactor parameter extraction
PLD: abstract get label from sort key
PLD: failing test for set sort criteria
PLD: tests for sort and refactor
PLD: use condp to DRY up sort-collection
PLD: abstract sort, no specific ids, closes #808
PLD: refactor hide message
PLD: remove namespace prefix
PLD: no func need for key map
PLD: expect 204 def so no mock
PLD: style and constants
Merge pull request #816 from onaio/808-sort-cleanup

808 sort cleanup