Add new operations that return raster tile loading operations.

These operations for data parallization on a raster return a list of operations
that each load a raster tile, and are designed to replace Raster.getTileOpList().
Remove and replace deprecated map/reducer classes.

This checkin updates all remaining operations that used the deprecated
Reducer1, Reducer2, tiles.Reducer1, and tiles.ThoroughputLimitedReducer1
classes.  This resolves the warnings and makes updating the Raster interface
to remove getTileOpList more straightforward.
Merge pull request #504 from joshmarcus/topic/remove_depreciated_reducers

Remove and replace deprecated map/reducer classes.