[RFC] I/O and Buffer Range

[Brian Schott]

I've been rewriting a bit of the lexer in DScanner.

https://github.com/Hackerpilot/Dscanner/blob/NewLexer/stdx/lexer.d
(Ignore the "invariant" block. I've been trying to hunt down some 
unreelated memory corruption issue)

One thing that I've found to be very useful is the ability to 
increment column or index counters inside of the lexer range's 
popFront method. I think that I'd end up using my own range type 
for arrays, but construct a lexer range on top of your buffer 
range for anything else.