Added cmdline.eel module

This handy utility module deals with command line arguments and similar.
At this point, it exports a procedure usage() that prints documentation,
and a function parse() that parses and checks arguments. Both take
argument specifications in the same format, which allows arguments to be
named, typed and provided with default values and descriptions.
Finishing the Audiality 2 binding - WIP
More TODO updates
cmdline.eel fixes, and finished renderwave2.eel
Implemented some more of the A2 stream API
Implemented Read() for A2 streams
Stream API seems to be done; streamtest.eel is working