Merge pull request #210 from pcpiela/master

User defined sorting for metric groups
Use the "chosen" widget for the metric picker
Change the cluster-view heatmap to use a tiles instead of an image. Each cell represents a server. When you mouseover a cell you see the name of the server and its current load.
Small amount of code cleanup
Use the "chosen" widget for the metric picker
Merge remote branch 'upstream/master'