Remove the RoseEngine and stream state pointers frose RoseContext, as
they are also present in core_info.
Unify stream state handing in Rose to always use a char * (we were often
a u8 * for no particularly good reason) and tidy up.
- cleanups
- add sparse iter instructions
- merge "root" and "sparse iter" programs together
- move program execution to new file program_runtime.h
- simplify EOD execution
- Use program for EOD sparse iterator
- Use program for literal sparse iterator
- Eliminate RoseRole, RosePred, RoseVertexProps::role
- Small performance optimizations