Update Bootstap to v2.3.2.

Taken from http://getbootstrap.com/2.3.2/customize.html and includes everything.
Update Respond.js to v1.3.0.
Update html5 boilerplate to v4.3.0.
Remove Bootstrap's normalize and use vanilla normalize v2.1.3.

This should do the job much better until Bootstrap 3.x is used.
Include Respond.js when needed and not for all browsers.