Fix download sequence button formatting bug

Fixes the strange float issue with the 'download sequence' button. Noticeable when the screen is narrow. 

issue  #3023

![screenshot 2014-08-13 13 33 12](https://cloud.githubusercontent.com/assets/617994/3909662/0b631d38-2310-11e4-941c-268fdc810548.png)
link to test:http://staging.wormbase.org/species/c_elegans/gene/WBGene00006763#-e-10