Added corelation capability when charting with matplotlib. Also deprecated graph_csv* methods. All new graphing modules should implement the graph_data method
Added the new graph_data method that will be called from metric rather than the graph_csv method
Added new PlotData class which is used for holding details of the the graph to plot
Replaced the call to Metric.graphing_modules[].graph_csv with Metric.graphing_modules[].graph_data which provides corelation support
Added config-gc-js, which uses the js graphing_module
Added config-sar-matplotlib, which uses the matlib graphing_module