Update proper semver versioning.

Bower requires you use [valid semver versioning]https://github.com/bower/bower/issues/144#issuecomment-10490902), however "1.8" does not suffice for this. You'll need 1.8.0. In the latest release of Bower, you get [all sorts of annoying issues](http://d.pr/i/Npyn) which mean history.js cannot be installed :(