Add diff method to ViolationList
Merge pull request #17 from Spy-Seth/add-diff-to-violation-list

Add diff method to ViolationList
Add equals method to Violation.
Merge pull request #18 from Spy-Seth/add-equals-method

Add equals method to Violation.
Strict comparison.
Merge pull request #19 from Spy-Seth/add-equals-method

Strict comparison.