Added methods to release GL textures, misc fixes
Added elapsed time control in flushDeletedTextureObjects
Added unit test to TextureManager, fixed bad access in release loop
Merge pull request #166 from jtorresfabra/releaseGL

Fixes for TextureManager and releaseGLObjects
Moves pixel configuration into Texture class

The problem is that using flipy for prepared cubemap is not
suitable. Moving the configuration in texture level let the user to
choose what he prefers. By default for texture y flip is activated, but
for texture cubemap by default it's false.

Conflicts:
	sources/osg/Texture.js
Added a readNodeURL callback
Modified PagedLOD to call to readNodeURL, just in case there exists a custom readNode callback
Adds better shader error reporting (surrounding lines + error listed in console)
Merge pull request #170 from cedricpinson/feature/shaderFailBetterLog

Adds better shader error reporting
Adds example to show how to debug scenegraph

This example need to be added as option in osgViewer to use it
dynamically on arbitrary scene.
Also a lot of improvement are needed:
 - add small button a la 'glDebugger' instead of big one
 - add more informations about nodes
 - improvement rendering of matrixes
 - handle better how d3/dagre can be loaded only when needed
Merge pull request #169 from jtorresfabra/readNodeCallback

Added a readNodeURL callback
Fixes codepath to load assets relative to node url
Improves/Cleans ShaderGenerator system

- Add Compiler object in ShaderGenerator to be replaced if necessary
- Add a filter system in Compiler to handle only Attributes
- Moves some functions from StateAttribute like
  Material/Blending/... into StateAttribute base classe
- Add shim 5/6 for tests (phantomjs) because of introduction of Map/Set
Setup shader generator example

- demonstrate how to add custom StateAttribute
- give an example how to add custom ShaderGenerator and controlling them
  from StateSet
- use two approach uniform for enabling an attribute or rebuilding of
  shader from flag
Merge pull request #174 from cedricpinson/example/shader-generator

Example/shader generator
Fixes quat normalization
Merge pull request #175 from cedricpinson/fix-quat-normalize

Fixes quat normalization
Updates grunt-connect to serve gzip correctly for examples
Fixed intersections in the case of polytopeointersector going through a triangle without containing any point of it
Fixes cubemap examples because of new flipY flag