Use variables for the expires date.
Increase expires dates.
Merge pull request #83 from XhmikosR/statics

Statics
Various CSS tweaks:

* add missing vendor prefixed properties for older browsers support
* use the shorthand properties in a couple of places
* be more explicit with the properties
* add a new variable for white color
* add fallback colors for RGBA
Show the outdated browser warning on IE < 8.

The site doesn't really work on < 8.
Update grunt-contrib-less dep.