Update index.html

This will remove Collapse text from the button. So it won't display an ugly symbol like in this picture: https://cloud.githubusercontent.com/assets/7201354/2716909/80cee1a4-c534-11e3-9d7f-3a9a1a54e14d.png
Merge pull request #2 from sevban/patch-1

Update index.html; Pull request confirmed.