Merged.

Silvia, you can tell Andrey that the change will be propagated to the public
repository soon after the IPC deadline. (If he needs it earlier, he can contact
us and we can send a patch, but probably this isn't urgent as it shouldn't be
too hard to avoid this bug.) Please send thanks to Andrey for reporting this!

Getting rid of this nesting during parsing already is fine.
I'll merge this later today. Thanks to both of you!

I fixed this in my repository by simplifying all conditions once when parsing
the task. Malte, is this proceeding ok, or did you want to preserve the
structure at this first step (except transforming conditions to NNF)?

With the attached input, an assertion fails in normalize.py in line 307:
"Condition not normalized". This concerns the nested conjunctions in the
precondition of the first action.

Bug reported by Andrey Kolobov.