fixes #0001422: Subclass Exception

inherit Base.FreeCADError form RuntimeError
inherit Part.OCCError from Base.FreeCADError
inherit OCCDomainError from Part.OCCError
inherit OCCRangeError from Part.OCCError
inherit OCCConstructionError from OCCDomainError
inherit OCCDimensionError from OCCDomainError
Added PY_CATCH_OCC macro
replace PyExc_Exception
use FreeCADError in makeWireString
catch exception in BSplineCurve.increasedegree

src/Mod/Fem/App/AppFemPy.cpp

@@ -85,7 +85,7 @@ static PyObject * read(PyObject *self, PyObject *args)
             return new FemMeshPy(mesh.release());
         }
         catch(...) {
-            PyErr_SetString(PyExc_Exception, "Loading of mesh was aborted");
+            PyErr_SetString(Base::BaseExceptionFreeCADError, "Loading of mesh was aborted");
             return NULL;
         }
     } PY_CATCH;