This patch adds support for:
- PyObject -> SBValueList (which was surprisingly not there before!)
- PyObject -> SBValue
- SBValue -> ValueObjectSP using the ScriptInterpreter
These three are the main remaining plumbing changes necessary before we can get to the meat of actually using ScriptedFrame to provide values to the printer/etc. Future patches build off this change in order to allow ScriptedFrames to provide variables and get values for variable expressions.