- replaced the testing if instance of FlatCAMObj with testing the obj.kind attribute

- removed the import of the whole FlatCAMApp file only for the usage of GracefulException
- remove the import of FlatCAMApp and used alternate ways
- optimized the imports in some files
- moved the Bookmarksmanager and ToolDB classes into their own files
- solved some bugs that were not so visible in the Editors and HPGL parser
- split the FlatCAMObj file into multiple files located in the flatcamObjects folder and renamed the contained classes with names more suggestive
- updated the Google Translation for the German language

tclCommands/TclCommandMillSlots.py

@@ -6,7 +6,6 @@
 # ##########################################################
 
 from tclCommands.TclCommand import TclCommandSignaled
-from FlatCAMObj import FlatCAMExcellon
 
 import collections
 import math
@@ -139,7 +138,7 @@ class TclCommandMillSlots(TclCommandSignaled):
         except Exception as e:
             self.raise_tcl_error("Bad tools: %s" % str(e))
 
-        if not isinstance(obj, FlatCAMExcellon):
+        if obj.kind != 'excellon':
             self.raise_tcl_error('Only Excellon objects can have mill-slots, got %s %s.' % (name, type(obj)))
 
         if self.app.collection.has_promises():