New way to register MayaScene custom attributes
Added python binding for MayaScene custom attributes, updated MayaSceneTest
Replaced MayaScene::hasAttribute for loop with find
Merge pull request #142 from valeriebernard/mayaSceneCustomAttributes

Maya scene custom attributes
Fixed bug #4837: "Knobs not found" warning messages.
The bug only appears when loading the LensDistort node UI for the first time with a file sequence specified. The cause was the early termination of the knob_changed() method before an update
to the dynamic knobs was made. The fix also the code simpler to read.
Fixed an issue where the artefacts were appearing around the edges of the bounding box despite the "black_outside" flag being turned on.
An additional result of this fix is that the distorted image is no longer clipped slightly around the edges.
MayaScene fixes for root, updated test for customAttributes
Merge pull request #144 from valeriebernard/mayaSceneCustomAttributesFix

MayaScene fixes for root, updated test for customAttributes
Fixed SceneCache build problem on OS X.
Removed IECoreGL/Lights.h.

It was unecessary before, isn't used anywhere, and refers to deprecated OpenGL functionality we wish to move away from.
Removed IECoreGL/GLUT.h.

We don't have a dependency on GLUT any more, and we should have removed the header when we removed the dependency. Also fixed inaccurate comment in IECoreGL.h.
Merge pull request #147 from johnhaddon/removeGLUTHeader

Removed IECoreGL/GLUT.h.
Merge pull request #146 from johnhaddon/removeGLLights

Removed IECoreGL/Lights.h.
Merge pull request #145 from johnhaddon/sceneCacheMacBuildFix

Fixed SceneCache build problem on OS X.
Merge pull request #143 from goddardl/LensDistortMissingKnobError

Fixed bug #4837: "Knobs not found" warning messages.
Added FnSceneShape createChild, extracted from expandOnce.
Fixed IECoreGL::PointsPrimitive crash on OS X.

It seems that some drivers don't like being passed 0 points to be rendered.
Merge pull request #149 from johnhaddon/zeroLengthGLPointsFix

Fixed IECoreGL::PointsPrimitive crash on OS X.
Merge pull request #148 from valeriebernard/fnSceneShapeCreateChild

Added FnSceneShape createChild, extracted from expandOnce.
Fixed IECore::Lookup for OS X.

I'm not sure why the compiler didn't like the templated constructor, but using boost::function instead fixes the problem and makes it more flexible anyway.