azavea/OTM2 — pull request #125 by RickMohr (2013-08-01 14:45:56+00:00)
Title: Search filters now apply to UTF grid as well as tiles

Previously we had an OpenLayers subclass of "Layer.XYZ" with the filtering logic.
I couldn't see how to make a similar subclass of "Layer.UTFGrid" without duplicating code,
so instead we apply the new function makeFilterableLayer to both XYZ and UTFGrid layers.