SWIG API Docs

[Robadob]

How are we going to generate api docs for the swig interface?

SWIG does appear to copy across doc comments to the generated python, but we haven't actually tested or setup doxygen on it and there may be some edge cases (e.g. I don't believe any of the extensions inside pyflamegpu.i have been documented as this was not considered).

[Robadob]

Started working on this in py_doxygen branch, have found some limitations.

• Doxygen does not detect it's 'special commands', as SWIG labels them as :command rather than @command or \command
• It appears there are many examples of commands such as AgentDescription::newVariable() where there are multiple versions of the same function, and doxygen isn't grouping them as assumed. So comments appear out of place (in both docs).
• SWIG template expanded functions have the argument *args which encapsulates all of their parameters, unclear how this can/will be documented properly.

For the time being, I think I will focus on improving C API docs, and SWIG only function docs to try and give better clarification of how they might look once other issues are solved.