Added SceneCache Transform SOP

This node applies transformations from a SceneCache file directly on the points and primitives at the SOP level. In "Name" mode, it applies a different transformation per named shape, using the name as a relative path to the SceneCache file and root. In "Root" mode, it applies a single transformation from the SceneCache file to the entire input.

Note that the loop to collect the named primitive ranges is duplicated from SOP_SceneCacheSource. I've added a todo about finding a common place to put them. I wasn't sure if I preferred another sort of DetailSplitter, or a common base class for these 2 nodes (SOP_SceneCacheNode). Or just too leave it as is until we have a 3rd use case...