do code cleanup

move BOPTools from Part to PartGui because it depends on GUI

src/Mod/Part/App/AppPart.cpp

@@ -383,22 +383,6 @@ PyMOD_INIT_FUNC(Part)
     Base::Interpreter().addType(&Part::Line2dSegmentPy::Type,geom2dModule,"Line2dSegment");
     Base::Interpreter().addType(&Part::Line2dPy::Type,geom2dModule,"Line2d");
     Base::Interpreter().addType(&Part::OffsetCurve2dPy::Type,geom2dModule,"OffsetCurve2d");
-#if 0 /* for python3 this isn't working anymore, it's solved by importing the BOPTools
-         directly. (import BOPTools) */
-// this causes double initialisation of the part modul with python3.
-    try {
-        //import all submodules of BOPTools, to make them easy to browse in Py console.
-        //It's done in this weird manner instead of bt.caMemberFunction("importAll"),
-        //because the latter crashed when importAll failed with exception.
-        Base::Interpreter().runString("__import__('BOPTools').importAll()");
-
-        Py::Object bt = Base::Interpreter().runStringObject("__import__('BOPTools')");
-        module.setAttr(std::string("BOPTools"),bt);
-    } catch (Base::PyException &err){
-        Base::Console().Error("Failed to import BOPTools package:\n");
-        err.ReportException();
-    }
-#endif
 
     Part::TopoShape             ::init();
     Part::PropertyPartShape     ::init();

src/Mod/Part/InitGui.py

@@ -41,13 +41,14 @@ def __init__(self):
     def Initialize(self):
         # load the module
         import PartGui
-        import BOPTools
 
         import CompoundTools._CommandCompoundFilter
 
         try:
-            BOPTools.importAll()
-            BOPTools.addCommands()
+            bop = __import__("BOPTools")
+            bop.importAll()
+            bop.addCommands()
+            PartGui.BOPTools = bop
         except Exception as err:
             FreeCAD.Console.PrintError("Features from BOPTools package cannot be loaded. {err}\n".format(err= str(err)))