[Python] move setting sys.argv[0] to XBPython::evalFile()

This is useful so sys.argv[0] is always set.

This does break the xbmc version check addon, since now sys.argv[0] is always filled. this is the way python should be, sys.arg[0] is usually the path to the script.

This just sets it to the <addon id> for scripts and plugin://<addon id> for plugins.

@garbear