New rubocop releases often break build

[kwauchope]

Sorry @stevenhaddox , just a quick one for you. The biggest headache with new builds is rubocop minor version releases adding new rules which then break the build. This is most annoying when a rubocop release is pushed out while developing so you are using a different development version to what ends up being used in travis and the build breaks when it 'worked on my box'.

I'm far from a ruby dev, I'm not sure your take and a quick google didn't bring up anything as far as resolving this issue but do you think locking to a specific rubocop minor version is a good move? If so it will need to be v0.41 to continue to support ruby 1.9.3, otherwise will have to drop 1.9.3 support and dnc can use a newer rubocop. I'm happy to implement either and put in a pull request.

[stevenhaddox]

@kwauchope: I want dnc to be usable across as many rubies as possible. I think locking rubocop to the version it was created against (or the latest you have working with it) is perfectly reasonable if it's not following SemVer in a friendly manner. If you want to modify the Gemfile to lock rubocop I can bump it manually whenever I want to get the latest and greatest community style checks. Happy to accept a PR for that change :)