initial timer implementation for game
simplify minutes and seconds calculations

minutes = timerSeconds / 60
seconds = timerSeconds % 60
refactor timer
- add protocol to handle sending minutes and seconds information to
  controller for its initial state and on every tick
- add params to init method for the intended delegate (controller
  instance) and the time, in seconds, from which to count down
- make method call to display initial time
- add convenience methods for setting minutes, seconds, and minutes and
  seconds together