Added IECoreNuke::SceneCacheReader
Added the SceneCacheReader for nuke versions > 7. The SceneCacheReader provides functionality to view, filter and display the geometry of SceneCacheFiles.
Merge pull request #48 from goddardl/sceneCacheReader

Added IECoreNuke::SceneCacheReader
Preventing crash when expanding a LinkedScene referencing a non-existant file.
Preventing crash when reading tags or links from standard nodes.
Fixed time dependency issue with ieSceneCacheTransforms.
Static state is now stored as a boost::tribool. This allows us to correctly set the time dependency flags during sceneChanged(), and detect when it is uninitialized during getParmTransform.
Fixed LinkedScene verification test.
LinkedScene started storing separate attributes rather than a compound. Updated the test, which required adding bindings for the various link attributes. Also renaimed timeAttribute to timeLinkAttribute as Lucio requested.
Fixed enabled state so it lasts across scene save/load
Merge pull request #53 from andrewkaufman/houdiniSceneRopCrashes

Houdini SceneCache Fixes