[ANALYZER-2391] - Data format is only applied to outer ring values in Sunburst chart
* Missing customFormat-spec.js file.
* Fix to def.instanceFields; cannot inherit from an instance of a different class.
* Fix to DimensionType constructor not receiving or handling the formatProto to inherit its format provider from.
* Improvements to pvc.BaseChart#loadData method so that it works better in situations where there is no data to load. This is used in the unit tests.
* Added pvc.BaseChart#format accessor (could/should probably patternize the accessor code, and create a helper for it; maybe it two of the kind are used)
* Some unit tests for the chart and dimension type options configuration.