Stop redirecting all IO to log.

We use the logger directly now.
Add Rakefile for airbrake/errbit tasks.
Merge pull request #9 from alphagov/add-rakefile-for-airbrake-tasks

Add Rakefile for airbrake/errbit tasks.
Merge pull request #10 from alphagov/stop-redirecting-all-io-to-log

Stop redirecting all IO to log.