Issue #173: Allow Shape_Length/Shape_Area field if defined by user.
Issue #173: Allow Shape_Length/Shape_Area field if defined by user.

CanterburyRegionalCouncil/arcgis-viewer-flex,Esri/arcgis-viewer-flex,Esri/arcgis-viewer-flex,CanterburyRegionalCouncil/arcgis-viewer-flex,CanterburyRegionalCouncil/arcgis-viewer-flex