0.5.1

Feature enhancements:

* Added or improved file type filtering for vim.
* [FEATURE BurntSushi#34](BurntSushi#34):
  Add a `-o/--only-matching` flag.
* [FEATURE BurntSushi#377](BurntSushi#377):
  Column numbers can now be customized with a color. (The default is
  no color.)
* [FEATURE BurntSushi#419](BurntSushi#419):
  Added `-0` short flag option for `--null`.

Bug fixes:

* [BUG BurntSushi#381](BurntSushi#381):
  Include license text in all subcrates.
* [BUG BurntSushi#418](BurntSushi#418),
  [BUG BurntSushi#426](BurntSushi#426),
  [BUG BurntSushi#439](BurntSushi#439):
  Fix a few bugs with `-h/--help` output.