Create bkoBubbleChart.js

This is a bubble chart output display which has the following features:
1. Requires table input
2. Throws an error message if number of columns provided is not 3
3. Has an option to select columns for X-axi and Y-axis. Assumes radius of Bubble after this selection.
4. Throws an error if same column is selected for X-axis and Y-axis.

Instructions to deploy and run this output display:
1. Use beaker to load flotr2.min.js and flashcanvas.js
2. Load this file bkoBubbleChart.js
3. Register output display as bkoBubbleChart
4. Provide table input in iPython in beaker and choose this output type for display