Always look for pre-existing undo/redo record. Checking for IsNew()
is less robust and should be avoided. Also moves the checking to a
location where it will be easier to ensure that it's uniform.
Push get-undo-level-item processing down a level so it is uniformly
called.
Make sure tables & labels are uniformly handled.
Remove incorrect usage of Get/SetGroupId() for storing lastPin
(which we don't use anyway).
Lists of deleted and changed items MUST include the screen pointer.
An item could be changed on one screen but not on another.
Also tightens handling of PCB_NETINFO_T items, which are not in the
view.
Also fixes a bug where there is no increment parameter if you assign
the base increment command to a hotkey.
(This was discovered while testing the above changes.)
Also fixes a bug where delete during a move in PCB Editor did an
undo instead of a delete.
(Again, found while testing above.)
An experiment was also run to collapse shared parts of SCH_EDIT_FRAME
and SYMBOL_EDITOR_FRAME into SCH_BASE_EDIT_FRAME. However, sharing the
undo code actually increased complexity, and there was very little else
of value in SCH_BASE_EDIT_FRAME (other than the Increment() routines).
Jeff Young