Simplify arg parsing with =
Simplify processing of --
Simplify arg printing loop
Shorten the trivial STDERR function
Fix handling of -- to not drop arguments

Kind of left off a crucial piece there. Do I need unit tests for this
thing?
Compress trivial usage function
Improve error messaging

Replace somewhat silly STDERR function with the more useful "error"
function which handles escape characters and formatting.
Handle fancier arg passing

Add support for GNU-style long options with args (like "--option=val"),
POSIX-style short option chaining, and arguments for short options
without spaces.