Initial bucketization changes

- Basic bucketization wherein the nodes are grouped together in buckets.
- Clicking on a bucketized node will zoom in displaying the next level of nodes.
- Double clicking on the chart will zoom out to the first level
- Options provided to the chart to enable display bucktization
- Color filter moved to options
- Axes changes pending

Change-Id: Ic755a3dcb37b9e5c581a7f882a8130329c9d2f5b