Implement two views: show summary of a changeset and show single certain file content #20

revizor-21 Add feature to view all the changeset without a review
correct the links "back" #20

revizor-21 Add feature to view all the changeset without a review
Add button "create new review" #20

revizor-21 Add feature to view all the changeset without a review
Highlight a selected file in a tree. Closes #20

revizor-21 Add feature to view all the changeset without a review