What would need to be done to get sdc.lexer to std.lexer quality?

[Bernard Helyer]

In my dev work I've shaved some bytes off of Token.
I removed the filename from Location, as we don't assume
the input is a file anymore, and I've changed to tracking
line and column numbers as uint instead of size_t.

I don't know what kind of number I _should_ be aiming for,
but I'd imagine I'm not gonna get it that small.