Refactor Overcommit framework
Add support for commit-msg hooks
Move to HookContexts
Move hook_type out of HookRunner
Begin adding specs for pre-commit hooks
Add specs for commit-msg hooks
Add BundleCheck post-checkout check

With specs!
Add IndexTags post-checkout hook
Improve CLI interface and specs
Improve specs for Installer
Remove some unused specs
Add specs for PreCommit and CommitMsg contexts
Replace deprecated mock with double
Add PostCheckout context specs
Add specs for ConfigurationLoader
Add partial specs for Configuration

Still have to add specs for `merge` and `apply_environment!`.
Add specs for Configuration#merge
Add specs for Configuration#apply_environment!
Remove commented lines from spec_helper
Add basic Rubocop config file