C style checker script

[ghudson@MIT.EDU]

I've been reviewing a lot of code contributions during this release
cycle, and I've found that it takes an inordinate amount of effort to
ensure that each contribution meets the technical details of our house
style.  I'm sure it feels like nitpicky busywork to contributors as
well.

In the name of reducing this wasted effort while still maintaining
code consistency, I've created and checked in an automated style
checker script.  It's not perfect, but it detects some of the most
common issues I tend to run across, such as overly long lines, as well
as many issues which are less common but happen to be easy to check.

It's easy to use if you use git, and can even be automated using a
post-commit hook.  If you are in the process of developing
contributions to MIT krb5 or find yourself doing so in the future,
please take note of the instructions here:

    http://k5wiki.kerberos.org/wiki/Coding_style/Style_checker

Feedback is also appreciated if the script gives you false positives
or you have an idea for improving it.