Fixed GLSL error in Ground_Scattering_Fragment shader - due to not implicit conversion of vec4 to vec3:

<log output>
FRAGMENT glCompileShader "atmos_fragment_main" FAILED
FRAGMENT Shader "atmos_fragment_main" infolog:
Fragment shader failed to compile with the following errors:
WARNING: 0:33: warning(#402) Implicit truncation of vector from size: 4 to size: 3
ERROR: 0:33: error(#162) Wrong operand types: no operation "+" exists that takes a left-hand operand of type "uniform 4-component
vector of vec4" and a right operand of type "highp 3-component vector of vec3" (or there is no acceptable conversion)
WARNING: 0:33: warning(#402) Implicit truncation of vector from size: 4 to size: 3
ERROR: error(#273) 1 compilation errors.  No code generated
</log>
Merge pull request #536 from BrandonTheHamm/master

Fixed GLSL error in Ground_Scattering_Fragment shader - due to not impli...
Renamed layers in composite.earth to make sure they can be packaged correctly
Merge branch 'master' of https://github.com/gwaldron/osgearth
Fixed multithreaded and multiprocessing modes in TileHandler by removing previous handleTile function that only takes the key in favor or new signature that takes both the key and the visitor.
fix for finding geos on Ubuntu 14.04
Merge pull request #538 from ldelgass/cmake-find-geos-fix

fix for finding geos on Ubuntu 14.04
Fix #511 namespace clash on iOS Simulator
Merge branch 'master' of github.com:gwaldron/osgearth
Fix #510 compile error on ios
URI: add support for osgDB option string
Fixed issue with WMS-T support where you'd end up with a black image if you got no images back from the server for a tile.
Merge branch 'master' of https://github.com/gwaldron/osgearth
Fix: compile error in OSG pre-3.1.4
Fix: fail to open TMS repo from zip archive
Add isFileInArchivePath
Support of null
Merge pull request #540 from remoe/patch-12

Support of null
LogarithmicDepthBuffer: fix error when large polygons intersect the near clip plane
Merge branch 'master' of github.com:gwaldron/osgearth