This allows .py files to be associated with an editor. Before this fix, twistd.bat simply "started" twistd.py, which would tend to open the file in an editor if the file associations were set.
This fix simply prepends the python interpreter path to the twistd.py path when twistd.bat is built programmatically so it is always "run as a python program" no matter the current Windows .py file association.
* The startup script (evennia.py) will now take your PYTHONPATH environmental variable into account when starting. This may resolve potential issues with Twisted on Windows with certain combinations of Python.
* The INSTALL file still referred to startup.bat, which is now gone in favor of evennia.py.
Thanks Ari!
