Navbar accents

This adds some shadows and indicators to the navbar to set it apart from the rest of the page and make it a bit more obvious. It mainly uses box-shadows. Note that if it isn't working there are `-moz-box-shadow` and `-webkit-box-shadow` rules which can be paralleled with `box-shadow` to do stuffies.

@cg505, how do you like it? I think it's pretty schmexy.