[#26] Adds a simple view of transaction revisions

Needs work, as the transaction-id is hard coded. Need help working
out how to pass this into the function.
Updates urls.py so that revisions can take a transaction id
[#26] Makes the view work properly!
[#26] Removes comment from code that is not needed
[#26] Removes comments and fixes flake8 errors
Merge pull request #27 from caprenter/26-transaction-revision-view

[#26] Adds a simple view of transaction revisions