Removed compatibility shim for RBSplitView

We used to use RBSplitView 1.1.4 for 32-bit systems and 1.2 for
64-bit systems for old OS support, but we no longer support 32-bit
systems at all.
Remove OXP components from Debug bundle

Preparing to embed bundle directly in app instead of loading it like
a plug-in.
Rename DebugOXP directory to DebugBundle
Remove references to Debug OXP