Second attempt at integrating BMSwingDie into BMGame

The basic logic for setting swing values is now present in BMGame, and the full Soldiers game  unit test incorporates the setting of swing values.

Note that activate() now takes no arguments, as discussed previously in #24, with the $playerIdx input variable now promoted to an object property. If wished, it is easy to add two parameters, i.e., activate($ownerObject = nil, $playerIdx = -1), and when the default values occur, then these become BMDie->ownerObject and BMDie->playerIdx.