Uncaught `StopIteration` in _DictionaryAccess.__init__ in invalid number of lines in dictionary

[mvondracek]

Please see 51ecf78, on branch bug-44.

[mvondracek]

Fixed by #48.

Bugfix should have included tests for the bug, which are on bug-44 branch. I'll merge bug-44 to task-40-more-tests branch, where I'm finishing tests.