[Lazarus] Groundwork for Undo in Form Designer

[Marc Weustink]

Juha Manninen wrote:
> Hi,
> 
>> Obviously, batching patches makes sense in such an environment.
> 
> Right, if I know I am on the right track with my edits.
> Otherwise, if I miss some dependency in the code or not fully understand the 
> design I could make some mistake.
> Then finally, after creating lots of code, the feedback would be like:
> "Thanks but no thanks. We planned to make it differently."
> or: "You didn't consider that one detail. Your code must be re-designed."
> 
> That is why I wanted feedback.

For reviews I personally prefer one unified diff (diff -U 5) of changed 
code (without code reformatting)
How you get this diff, I don't care. I certainly don't want to look in 
some other repro. It's simply to much work.

Marc