Fix for Bug:1337819 - Using DateTime picker utility to provide only valid values.

Change-Id: I0bf972a9c2f0ef373c1ac80534a5d0d0a2c65e07
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: I48c00e7b6a545c508152a0cef71c98cd46095460
Merge pull request #11 from manojgn/feature-dev

Initial bucketization changes