new node_management page; new nav icon; barebones ember setup for routing to new page; fixed responsive problem on ring page
changed all instances of node_management to nodes
finished markup for node management page
created a new file for ember mixins shared amongst node/cluster views and controllers.  also changed underbars to camelCasing in many places
Merge pull request #76 from basho/jgn-node-management

New markup for a node management page