- modified camlib.py, FlatCAMApp.py and ObjectCollection.py files to the new string format that will allow easier translations

- updated the POT file and the German language

ObjectCollection.py

@@ -762,7 +762,8 @@ class ObjectCollection(QtCore.QAbstractItemModel):
             try:
                 a_idx.build_ui()
             except Exception as e:
-                self.app.inform.emit(_("[ERROR] Cause of error: %s") % str(e))
+                self.app.inform.emit('[ERROR] %s: %s' %
+                                     (_("Cause of error"), str(e)))
                 raise
 
     def get_list(self):