Added support of PIXEL_SIZE_ON_SCREEN range mode in mp driver
BUG-FIX: the minimum LOD option is now applied correctly when engine mp is used.
Fixed a typo in a comment
Merge branch 'master' of https://github.com/gwaldron/osgearth
Fix g++ build error
Removed "fix" for the min LOD option.
Commit untracked fiels for merging
Merge remote-tracking branch 'hpicgs/master'
Merge remote-tracking branch 'origin/master'
Locking makeDirectory calls in the TMSPackager to avoid "Warning: Could not find plugin to write image" errors
Merge branch 'master' of https://github.com/gwaldron/osgearth
Added new use_texture_arrays option.

Allows you to disable texture arrays in the ExtrudeGeometryFilter.
MP: fix memory leak in which the first TerrainNode is never deleted after a terrian refresh
Merge branch 'master' of github.com:gwaldron/osgearth
Added optional max size of the TaskRequestQueue to ensure that the queue doesn't grow unbounded.
Merge branch 'master' of https://github.com/gwaldron/osgearth
Activate hardware texture compression for terrain tiles
Merge branch 'master' of github.com:gwaldron/osgearth
cleanup
Removed unnecessary backup file