0023105: Exception during Meshing / Missing triangles

Fix compilation error on Linux
Adding test command for this fix
meshPolygon: simplify source polygon by splitting it onto parts without glued edges and loops
Check surrounded triangles during final cleaning of mesh
Correct polygon on frontier edges
Modified test cases in group mesh according to new behavior

src/BRepMesh/FILES

@@ -1,7 +1,11 @@
 BRepMesh_PluginEntryType.hxx
 BRepMesh_PluginMacro.hxx
+BRepMesh_Triangle.hxx
+BRepMesh_Triangle.cxx
 BRepMesh_ClassifierPtr.hxx
 BRepMesh_CellFilter.hxx
+BRepMesh_Delaun.hxx
+BRepMesh_Delaun.cxx
 BRepMesh_CircleInspector.hxx
 BRepMesh_MapOfIntegerInteger.hxx
 BRepMesh_MapOfInteger.hxx