Fix Bug 1072988, show conditional content based on old Fx or non Fx browsers

@chrismore r?
This has one small problem in skinny browsers.

![screen shot 2014-10-03 at 9 48 32 am](https://cloud.githubusercontent.com/assets/317532/4507457/b2fcccb4-4b0c-11e4-9fae-8136044134ed.png)

Changing to `nonFxDownload.css('display', 'inline-block');` seems to do the trick. Sorry I didn't catch this sooner.