Chart Events and Handlers

[harsha.galla]

I agree with fatzopilot.
Graphs need to be improved a lot. This could be the first step towards that.
Currently only line graphs have this functionality.

Other features that would be nice to have:

1) Ability to show values on bars, pie etc.
2) Ability to plot data in the graph as input by setData, instead of some generic logic used by smartgwt to order the bars etc.

[fatzopilot]

Would be nice to have events and corresponding handlers available for certain chart types. E.g. in case of bar charts, a onClick handler could be used to create a drill down functionality.