Rewrite of the scripting and conditions system.
Scripts are now actual python source files that are run inside a game environment.
Instead of conditions the scripting system now has a eval method that accepts a python statement which is run in the same environment as scripts.
Merge branch 'lighting' into scripting

Conflicts:
	fife_rpg/rpg_application.py
Adde a "set_global_lighting" command to scripts.