Ignore existing whitespace format errors

[ianconsolata]

We have a very large contingent of engineers in our company who don't want a single large whitespace commit because it obscures the git history. But we would like to enforce style guidelines going forward. Rubocop (https://github.com/bbatsov/rubocop) allows you to generate an excludes file based on the current state of the codebase. Is it possible to do the same with cljfmt?

[weavejester]

Not currently, but I'd accept a PR to that effect.