Stvpoll

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- Fixed bug with tie in first round on Scottish STV.
- Fixed bug in quota selection of all seats in CPO.

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- Unreleased

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- Fixed bug in deciding which vote to transfer first when multiple elected in Scottish STV. [schyffel] [robinharms]
- Scottish STV: Resolve ties so that winners are always in correct ranking order (extreme case). [schyffel]
- Now works on Python 3. [schyffel]
- Test coverage 100 %. [schyffel]

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- Fixed a situation where primary_candidate in rounds didn't exist. [schyffel] [robinharms]

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- Excluded empty ballots, so that they do not affect the quota. [schyffel]

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- Fixed exception on empty ballots. [schyffel]