Preventing double cooking in HoudiniScene::scene( path )

Previously the scene method was not using the default cook time for a portion of its calculations, resulting in double cooking of SOPs which contain a flattened hierarchy. Note that the additional test doesn't actually demonstrate the issue, as it is only apparent in an interactive session, because the viewport forces extra cooks as well. I've verified the cook count is appropriate in interactive mode, and added the test just to be sure no other extra cooks are being caused by the scene method.
made LinkedScene( SceneInterfacePtr ) support writable scenes
Merge pull request #191 from andrewkaufman/houdiniSceneDoubleCook

Preventing double cooking in HoudiniScene::scene( path )
Fixed SceneCache from IndexedIO bug, added a test
SceneCache SOP transforms all Point, Normal, and Vector primitive variables.

Previously it was only transforming P and N.
Merge pull request #193 from davidsminor/linkedSceneFromIndexedIO

LinkedScene can now wrap writable SceneCaches
Merge pull request #192 from andrewkaufman/sccSopPrimVarTransform

SceneCache SOP transforms all Point and Normal primitive variables.
Updating beta versions and changes
Fixing IE options for non-3delight builds
Removed deprecated uses of GEO_AttributeHandle
Fixing deprecation issues with UT_PtrArray
Fixing macro to exclude old files
Fixing use of UT_String tokenizer
Updating GU_CortexPrimitive

Added missing virtual functions, removing deprecated functions, handling changes in GU_ConvertParms, and GU_Primitive factory create signature
Adding friendship with bindings for access to private constructor.

I was never really sure why this wasn't required before, but I guess a gcc 4.4 is a bit pickier
Fixing FromHoudiniGroupConverter tests to account for difference in default attributes
Including SYS_Types to avoid compile issue in H13.0.256
Fixing IMG_DeepShadow interface changes
Using new IMG_DeepPixelWriter
Fixed numerous struct vs class mismatches.