#3297 Make casing shoe a right-angled triangle and refactor symbols

* Put plot symbol enum inside the symbol class.
* Put line style enums inside the line class.
* Add custom capability.

ApplicationCode/ProjectDataModel/Summary/RimSummaryAddress.h

@@ -34,7 +34,7 @@
 class RifSummaryReaderInterface;
 class RimSummaryCase;
 class RimSummaryFilter;
-class RiuLineSegmentQwtPlotCurve;
+class RiuQwtPlotCurve;
 class RimSummaryCurveAutoName;