Added hashCode and equals implementations

[farazdurrani]

Added hashCode and equals implementations so adding a duplicate to Set stops it from adding.

This checklist is used to make sure that common guidelines for a pull request are followed.

• [x] I have read the contribution guidelines.
• [x] Title of the pull request is clear and informative.
• [ ] There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR.
• [x] The pull request does not introduce breaking changes (unless a major version change occurs in the assembly and module).
• [x] If applicable, the public code is properly documented.
• [ ] Pull request includes test coverage for the included changes.
• [x] The code builds without any errors.