[crossfire] Plugins

[Nicolas Weeger]

Hello.

I cleaned the Python plugin, removing the dependancy on libcross
library. Didn't yet clear logger & animator (actually never tried to
compile'em under Windows lol).
And I won't touch plugin before the next release (or maybe to fix a
few bugs).

This leads to some questions:
* plugins will share some functions, to call the server (note: plugins
should *never* call directly server functions, this breaks under
Windows except rare cases). So maybe there should be a small libplugin
or whatever, which contains the binding functions. This should be
distinct from libcross which is used for random maps standelone, and
crossedit.

* what functions should a plugin be able to access? I'd say the more
the better, to have nice effects. But a plugin should not be concerned
with server logic - it should just issue simple orders.

* should we take care that a plugin can't crash the server or make it
a mess? This would mean active verification of object state after
calls, and take time to implement. Or we could just let plugins access
functions, the script developer being responsible for not crashing
server. Simple example: remove player object. That's a bad thing to do
- should a plugin be able to do that, or should the server forbid it?

Ryo