Corrupted double-linked list

[adewit]

If running ./bin/HTT on a local file with EventChecker enabled it will run to the end and write the output tree, then crash complaining about a corrupted double-linked list. This never happens when running off files on dcache, or when running on a local file without using EventChecker.
So there is some memory problem, though atm I fail to understand why this is only a problem under these very specific circumstances.

Anyway, low priority, but one to fix should we run out of stuff to do.