Previously, the findInterimTiles method was returning undefined if the min x/y coord for a tile range was already in the lookup. The return says it indicates whether all tiles for the given z are loaded. This change corrects the return.
This change also reveals a misunderstanding of the tile range returned by `getTileRangeForExtentAndZ`. The previous findInterimTiles method was treating max values as inclusive. This is intuitive. It looks like the method returns a range where max values are exclusive.
With this commit test files provide namespaces (using goog.provide). This fixes the issue reported by @bartvde where goog objects cannot be used in Jasmine "describe" functions. It also frees us from having to add script tags for the test files in test/ol.html.
