Revert configurable WMS transparency fix.
Refactored BasicElevationModel.

Removed the computeLevelForResolution() and getTilesInSector() methods
from the BasicElevationModelBulkDownloader class and moved the
functionality over to the BasicElevationModel class itself. This is to
correspond to the BasicTiledImageLayerBulkDownloader class that calls
the TiledImageLayer's computeLevelForResolution() and getTilesInSector()
methods. The advantage of this refactor is that given the
elevation-layer we can now get all the levels and tiles, whereas in the
past we could only do this for image-layers.
Changed versioning to be SNAPSHOT.

Changed the versioning to be 2.0.0-SNAPSHOT. This allows snapshot
releases to be deployed to a nexus repository with an automatic
timestamp attached to the version. This basically mirrors the
functionality of the NASA daily WorldWind builds. Except, now you can
perform the daily build yourself and deploy to your own internal
repository.