[crossfire] Doxygen-generated documentation

[Nicolas Weeger (Laposte)]

Hello.

I just committed a Doxyfile for the server, and modified c_object.h to use 
Doxygen's syntax (trunk only).

I think it'd be great to use Doxygen's syntax to document (non trivial) 
functions, especially:
* what special condition they expect (object is already removed from map, ...)
* the return value
* any side-effect (uses static buffer, ...)

Of course, that could be done through the incoming refactoring :)


Nicolas