Assorted fixes

Fixes for a bunch of issues:

* When viewing an image page (e.g., http://neurovault.org/images/1/), the top right corner displays the user who owns it rather than the user who's currently logged in (e.g., when I navigate to the page, I see ChrisFiloGorgolewski instead of TalYarkoni).

* Labels on the edit collection screen were hidden and cryptic because the verbose field names were non-human-readable. Updated them all to be more readable.

* Improves appearance of collection edit submit button