[MODCLUSTER-209] added boostrap 3.1.1 to managers ui

it is an attempt to make managers UI a bit more colorful, which of course comes with its own tradeoffs as was mentioned in https://community.jboss.org/thread/241145

UI introducing grouping of nodes under LBGroups with use of panels, switching contexts to tables, and changing command links to buttons.

![alt text](https://community.jboss.org/servlet/JiveServlet/showImage/2-874317-23040/Mod_cluster+Status+%2820140519%29.png "Screenshot")