Collage v0.4.0

Fixed:

• Upstream bug (Sprite Ids are now refs)
• Fixed an issue where sprites added via the IDE would be deleted if isCopy wasn't filled.

Added:

• CollageRenderPipelineInstance.RemoveImageByIndex(bufferEntry, imageEntry) added as per #19 (Thanks @thennothinghappened!) Note: Additional helper functions will be included in the future.