The undo/redo operations are essentially the same as for
UR_CHANGED: we store both the origin marker item and a copy
of it and flip back and forth between the two. This also
required the implementation of clone() for the markers.
The ORIGIN_VIEWMARKER is moved from being a subclass of
EDA_ITEM to BOARD_ITEM to facilitate the use of a UR_CHANGE-
like implementation without having to know the internals
of the ORIGIN_VIEWMARKER.
In the command processors, the setting of the origins is
broken into two parts: one for UI-level access which includes
setting up undo, and one for low-level access which does not.
The undo/redo code itself of course uses the lower level.
Fixes: lp:1542018
* https://bugs.launchpad.net/kicad/+bug/1542018
- added TOOL_INTERACTIVE::resetTransitions()
- made protected and moved TOOL_BASE::setTransitions() to TOOL_INTERACTIVE
- TOOL_MANAGER calls TOOL_INTERACTIVE::resetTransitions() instead of
setTransitions()
This means that non-top-level tools, for example EDIT_TOOL and
PCB_EDITOR_CONTROL can submit their own menus to the top-level tool's
TOOL_MENU, which will then retain a reference to it and make it
available for the CONTEXT_MENU that is shown.