[Planner Dev] A plan to finish UNDO world

[Alvaro del Castillo <acs lambdaux com>]

Hi guys!

Last week I have a big train trip so I have good hours to hack in
planner and the results are:

1. A second phase in the undo world implementing some missing things
like undo/redo editing resource dialog or implementing all the free
methods that clean the undo commands when we don't need them anymore.

2. A plan to finish the first complete version of the undo system.

The patch depends in another undo patch that I have sent this morning so
when we have commit these first patch, I will send the other to the
list. 

The plan to finish undo is attached in this email and I think now others
can help because for example, the undo work in some dialog could be done
by one developer without disturbing the work in other places. So if you
want to help, take a look to the plan: point 5 and 6 are the ideal ones
to help.

Cheers

-- Alvaro

1. In general, take care of undo commands that do nothing.
Ideally, if an action produces no modifications, it hasn't 
to be inserted in the undo system.

2. Finish the resource editor:
	- Custom properties
	- Calendar
	- Note

3. Finish resource view:
	- Something to do?

4. Finish the tasks view:
	- Link/unlink tasks
	- Constraints
	- Cuntom properties

5. Finish the task editor:
	- All to be done! ;-)

6. Implement other dialogs undo:
	- Calendar
	- Project properties
	- Day types
	- Project phases