Fixed bug with swing values being lost during a round

Fixes #1224. Fixes #1073.

If this pull request is merged immediately, it will cause conflicts with the refactored unit tests in BMInterfaceTest, since there is a new unit test in BMInterfaceTest that uses BMInterface->create_game(). If it is merged after both the refactoring of BMInterface and #1281, it will need to be altered such that the unit tests in BMInterface and responderTest (in cgolubi1/1224_reproduce_bug) have valid syntax and pass.

I am happy either way, and it's just a question of whether this bug fix can wait until the bigger changes are in.

http://jenkins.buttonweavers.com:8080/job/buttonmen-blackshadowshade/426/