Repo Browser and Student Assignment Page Fixes

Repo Brower:
    - Can now correctly look up revisions by timestamp with errors.
    - Correct directory and file structure now displayed.
    - Fixed bug with Error 404 (incorrect links) for files within sub-directories.

Student Assignment Page / File Browser:
    - Page would not load previously due to a incorrectly implemented method (date retrieval).
    - Confirmed students are able to upload files to their repos from browser.