Adds a second form of generating transitions, each transition in a separate POU.
- Patch isn't very long due to previous work.
- Readable by commit.
- Kept the "all code in main" form in order not to lose our test-base. Also, not convinced we can do without more than one form.
End-user visible is the new 'Event transitions form' option.
Addresses #935 (closed), #912 (closed)
Edited by Dennis Hendriks