Video now plays in IE6/7/8 (and STILL plays in other browsers :O)

Depends on #471 (IE nav bar tweaks). Fixes #48.

There was an incompatibility between Video.js v3 and IE8 and below. Tried upgrading to v4, but then there was a compatibility problem on Android browsers. Solution: utilize IE conditional comments to use v4 in IE, and v3 in other browsers.

Added a few extra fixes to improve rendering in IE (including a custom stylesheet to increase button size, and styles to use an alternative to the button webfonts, in IE7 and below).

Note: for video to work in IE8 and below, Flash must be installed. http://caniuse.com/mpeg4