Change the strategy for the U+FFFD separator handling.

Use a global variable instead. In SL, the optimizer does the replacement automatically, therefore no memory penalty is incurred. In OpenSim, the variable is assigned at run time with llUnescapeURL. The OpenSim separator is also changed from U+001F to U+007F, because most control characters under U+0020 cause problems with exporting when present in script memory.

Fixes #41.

AVsitter2/build-aux.py

@@ -48,10 +48,6 @@ def oss_process(filename):
         if filename is not None:
             f.close()
 
-    # The U+FFFD character that AVsitter uses causes problems in OpenSim.
-    # Replace it with U+001F (Unit Separator) which works fine.
-    s = s.replace(b'\xEF\xBF\xBD', b'\x1F')
-
     # UUIDs in OpenSim
     s = s.replace('f2e0ed5e-6592-4199-901d-a659c324ca94',
                   '206fcbe2-47b3-41e8-98e6-8909595b8605')