Add Pause Match button

[hsgarn]

Pause button in Match Panel. If match timer is running, it will pause it and relable to UnPause. If match timer is not running, it will start match timer and set label to Pause.
Pause should also pause the time since last shot timers.

[hsgarn]

Pause button pauses match, game, and last scored timers. However, if score incremented while pause, last score timer will unpause and will run while other timers paused. Then pause will start 2 timers and pause 1. Need to go to definitive state model.

[hsgarn]

Basic functionality in place including changing label from pause to unpause. However, there is one known issue that will be entered as a separate bug. The first press of pause button after starting a match seems to be ignored except for added the command to the statck.