Merge pull request #732 from johnhaddon/pathFilterNodules

Removed PathFilter paths nodule.
Updated link to dependency source code
Simplified and updated build script.
Fixing off-by-one issue in SceneReaderPathPreview frame range
Merge pull request #733 from andrewkaufman/scenePreviewFix

Fixing off-by-one issue in SceneReaderPathPreview frame range
Moved OSLImage::shadingEngine() to OSLShader::shadingEngine().

It makes more sense there as the shade node is the one responsible for representing shaders, and it was weird that OSLObject had to use OSLImage functionality.
WIP
WIP WIP