Unified HTML-character-escaping

It used to escape the data twice, once in psowrte and once in psogen.
Now, the whole escaping for the ShoutBox is now done in psogen.py

Plus: We forgot to escape color, it's also fixed.

Conflicts:
	piratebox/piratebox/python_lib/psogen.py
	piratebox/piratebox/www/cgi-bin/psowrte.py