fix IE7 display bug on history

I also updated the gov buildings id to just buildings as Neil wants the url to be #buildings

https://www.pivotaltracker.com/story/show/45251687
Merge pull request #376 from alphagov/fix-IE7-display-bug-for-history

fix IE7 display bug on history

https://www.pivotaltracker.com/story/show/45251687