[crossfire] Plugin system rewrite

[Nicolas Weeger]

Hello.

Gros / Lauwenmark and I are currently rewriting the plugin system, both
the server-plugin API and the Python plugin. It'll feature much
improvement (using Python objects instead of plain values, so that
you'll be able to do: Map.Width instead of CFPython.MapWidth(Map)).

So please don't touch too much plugin stuff while we finish :)

Nicolas