FTFY: an automated style corrector

This is a utility for applying a limited amount of style correction on
a change-by-change basis. Rather than a big-bang reformatting, this
tool attempts to only correct the style in diff hunks that you touch.
This should make the cosmetic changes small enough that we can mix them
with functional changes without destroying the diffs, and there's an
escape hatch for separating the reformatting to a second commit for
purists and cases where it hurts readability.

At this time, the script requires a clean working tree, so run it after
you've commited your changes. Run without arguments, the style
corrections will be applied and left unstaged in your working copy. It
also supports the --amend option, which will automatically amend your
HEAD with the corrected style, and --commit, which will create a new
change dependent on your HEAD that contains only the whitespace changes.

There are a number of ways this could be applied in an automated manner
if this proves to be useful, either on a project-wide or per-user
basis. This doesn't buy anything in terms of real code quality, the
intent here would be to keep formatting nits out of review comments in
favor of more meaningful ones and help people whose habitual style
doesn't match the baseline.

Requires astyle[1] 1.24 or newer.
  [1]: http://astyle.sourceforge.net/

Change-Id: I2fb3434de8479655e9811f094029bb90e5d757e1