#213 Kdiff3 crashes after defining manual alignment nested inside another one

[Sir Zooro]

Kdiff3 crashes after defining manual alignment nested inside another one. Steps to reproduce:
- open two files
- add "outer" manual alignment for left pane, e.g. lines 10-20
- add "outer" manual alignment for right pane, e.g. lines 8-25
- add "inner" manual alignment for left pane, e.g. lines 14-16
- add "inner" manual alignment for right pane, e.g. lines 13-15

Current result: kdiff3 crashes after performing last step.

Expected result: kdiff starts using new manual alignment. It may do this by splitting outer alignment into 3 smaller ones.

Kdiff 0.9.97, Windows 7 Pro SP1 with all patches.