This is useful if you want to build a mutt which can write
~/.muttdebug[0-9] log files to see what is going on behind
the scenes.
ClosesHomebrew/homebrew#3865.
* Use new "url" features
* Use keg_only DSL
* Use "skip_clean :all" DSL
* Whitespace and style cleanups
* Make bash invocations less silly
* Use new man2-man8 helpers
* Remove "FileUtils." since it is included in Formula
* Use real names for deps instead of aliases
* ENV.x11 now updates path, so remove that from individual brews
brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.