From Stephan Huber, "recent commits regarding GLuint64EXT broke the build for GLES1 and GLES2. Attached you’ll find a fix which hopefully work for every platform."
Disable depth test for rendering of hull backface
Removed nolonger used code paths
Changed the default directory for the output files to be the current working directory,
with the --write-to-source-file-directory added to allow one to have the original behaviour
of writing to the same directory as the original source file.
Integrated multipass volume rendering shaders from OpenSceneGraph-Data
Merge branch 'master' of https://github.com/openscenegraph/osg into Dev
Fixed build error due to typo.
Fixed build error
Build fixes for when ref_ptr<> has no auto type conversion
Added support for osgVolue::SampleRatioProperty.  Fixed build errors when compiling with ref_ptr<> automatic type conversion.
Build fixes for when ref_ptr<> automatic type conversion is turned off
Added support for sampleRatio and sampleRatioWhenMoving <volume> properties
Refactored .p3d loader to make it less strict about the tag, property and value strings when matching them to supported values.

Examples of supported matches are:

   <Slide> and <slide> will be treated the same
   <bgcolor>WHITE</bgcolor> and <bgcolor>White</bgcolor> will be treated the same
   <text alignment="TOP_LEFT"</text> and <text alignment="top left"</text>,  <text alignment="TopLeft"</text> will all be treated the same
Made protected methods virtual to allow subclassing to customize more aspects of the window setup.
Added GL_TEXTURE_2D_MULTISAMPLE to texture mode list.
Added clean up of osg::Program that are applied by the GLObjectsVisitor, which addresses a state leak that creates GL error once the main scene graph is rendered.
Cleaned up the Qt find package, and made changed the default threading model to SingleThreaded when using Qt5 to avoid crash due to regresssion since Qt4.
Cleaned up debug message.
Changed the TransprencyProperty range to 0 to 2.0 to enable forcing opaque qualities on fragments
Removed debug message