Retab according to vim standard.
Remove mmap/mlock for Windows compat.

Need to define a nice "secret buffer" iface and use that instead.
Nightly compatibility.

transmute now in mem:: not cast::

~[T] return value no longer a thing; need to use box, but why
allocate? Just pass in a mutable input. Need to do a pass over
data structures and figure out what needs to be mutable and what
doesn't.