Added: seeders health & Tooltip plugin

From <a href="https://github.com/popcorn-time/popcorn-app/issues/15"> issue #15</a>
Added seeders health as icon with 4 states and colors:
bad -> red
medium -> yellow
good -> limegreen
excellent -> green

On hover you will see the health status as tooltip (image 3):
![captura-de-pantalla-2014-02-28-a-la s -22 00 54](https://f.cloud.github.com/assets/1398677/2300043/9311c51e-a0dd-11e3-9718-7ed030652fca.jpg)

Also added the tooltip plugin from bootstrap. So now is available for front-end development using data-toggle="tooltip". <a href="http://getbootstrap.com/javascript/#tooltips"> More info here</a>