Refactor: Remove ByteFlow and FlowInfo classes.

[kc611]

As titled,

The ByteFlow and FlowInfo classes can be removed to reduce complexity. All of the methods of the classes can either be made part of the SCFG object or can be made into a function rather than a part of the class.

[esc]

The additional bit is that the Python bytecode itself can be stored as metadata on the PythonByteCode blocks. This will allow those classes to be removed entirely.

I think that the ideal API would be:

scfg = SCFG.from_python_function(python_func)

Or:

scfg = SCFG(python_func)

Also, this means, the ByteFlowRenderer can be removed too because PythonBytecodeBlocks will have the bytecode embedded and as such contain all the information they need to supply to be rendered.