fix authors with periods in names

[sneakers-the-rat]

Fix: #1346

The problem was that names with periods in them were interpreted as being a file extension (perhaps reasonably?) by the router. So clicking on "Author T. Lastname" in a paper would be interpreted by rails as {author: "Author T", format: " Lastname"}

So i added a constraint that matches any string excluding the three formats that it looks like there were responders for and added tests - don't know if i put the tests in the right spot, there weren't any tests for the papers/by/:author route so i just put it with the controller.

edit: i find ruby's formatting norms to be bewildering and bad, and i didn't notice a linter config in this repo, so sorry if my indentation is weird, feel free to request edits.

[arfon]

Oooo, nice! Thanks for spotting (and fixing) this.