Move RasterData classes to geotrellis.raster package.
Refactor geotrellis.raster classes into separate files.
Update subprojects to reflect RasterData package change.
Resolve -feature scala warnings.
Remove language feature warnings from tests.
Minor fixes as per code review.
Merge pull request #535 from joshmarcus/topic/rasterdatacleanup

Move RasterData to geotrellis.data and general clean up.
Update signature of Collect to take an Operation.

Collect is updated to take an operation that returns a sequence of ops, instead
of taking a sequence of ops directly.

CollectArray is deprecated in favor of using logic.Collect directly.
Update signature of Mean and Variety to take Seq[Raster].

Mean and Variety now take Seq[Raster] instead of Array[Raster], and no longer
use the depreciated CollectArray.
Merge pull request #536 from joshmarcus/topic/collect

Update signature of Collect to take an Operation.
Merge remote-tracking branch 'upstream/master' into localops/majorityminority
Updated for merge of upstream