[phobos] [D-Programming-Language/phobos] f3aa58: make invariants const-correct

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/phobos
  Commit: f3aa58592faed9a418e347090cd614670947fef4
      https://github.com/D-Programming-Language/phobos/commit/f3aa58592faed9a418e347090cd614670947fef4
  Author: Walter Bright <walter at walterbright.com>
  Date:   2012-01-29 (Sun, 29 Jan 2012)

  Changed paths:
    M std/mmfile.d
  M std/stream.d

  Log Message:
  -----------
  make invariants const-correct