ShaderGen: added support for remaining TexGen modes
Cmake: fix conditional include error w.r.t. libnoise
MouseCoordsUtil: print fixed coords by default, not latlong
Added compute_levels option to the MBTiles driver.
Added MBTiles driver docs.
DetailTexture experimentation
Merge branch 'master' of https://github.com/gwaldron/osgearth
Fix #447 VerticalDatum API errors
Merge branch 'master' of github.com:gwaldron/osgearth
Fix: TerrainLayer was not allowing vertical datum override in all cases
Fix: error in StateSetCache was preventing SA sharing.
Fix memory leak in FeatureTileSource
Added a simple PoisonPill capability to the TaskService

The PoisonPill allows you to write producer/consumer patterns with the
TaskService as the consumer and signal the end of work using the
PoisonPill task.
Minor doc/fromconfig tweaks
Merge branch 'master' of github.com:gwaldron/osgearth
Updates to the TMSPackager to be able to start packaging immediately without waiting to collect all the tasks up front.
Merge branch 'master' of https://github.com/gwaldron/osgearth
Add new files for EnvironmentNode
Refactor Sky to inherit from Environment, and add the SilverLining plugin.
SilverLining: support user/license string