Add Part_RegularPolygon,

regular polygon edge in Part workbench "create primitives",

Add icons Part_Polygon and Part_Spline
rebase auto merge error fixes

Signed-off-by: jmaustpc <jmaustpc@users.sourceforge.net>
minor error hide Height PrimitiveFeature.h
rebase auto merge error fix AppPartGui.cpp

add ViewProviderRegularPolygon
minor code clean ups removing previously hidden unwanted code

PrimitiveFeature.cpp
PrimitiveFeature.h