Change game play flow (to allow for power-ups)

This is a setup task to allow power-ups (to be implemented for #14).

I've been working on this for the last week or so and basically the new flow requires the player to end their own turn. This means that the player can now choose not to use all possible moves. The reason I have this flow is because it will give the player the opportunity to use their power-ups during their turn. It also gives a new layer of strategy because players are no longer forced to use all possible moves for a turn.

I have not yet pushed the commits I've worked on so far (there are quite a few) because I'm still working out some UI issues.

Zooce / vexation

Change game play flow (to allow for power-ups) #21