New Bootstrap skin, and now using Grunt.js for LESS/CSS and JS.

Grunt.js gives us the ability to now compile, concat, and minify all
assets. After installing Node.js and Grunt, just run the following
to compile changes in LESS or JS files:

$ npm install
$ grunt [watch]

Using the optional "watch" task, files will be monitored for changes
and recompiled for immediate feedback.

Also now that Bootstrap and Font Awesome are compiled from their
native LESS source files, we can quickly make small changes to several
theme-related settings including colors, margins, sizes, styles, etc.
See the _assets/less/theme-customizations.less for details.

The new skin in use is "Flatly" with some minor modifications.