Issue #81 -- Play a sound when remaining time in turn = x

This introduces the ability for a user to receive an audio alert and flash Hearthstone when their time left in a turn reaches X seconds. 

- Added Checkbox and Textbox controls to Options.xaml
- Added config values for Textbox (int) and Checkbox (bool)
- Added event handlers for both to limit input to digits as well as save values and disable textbox when unchecked
- Added a check during TimerTick to play sound and flash when it reaches their specified time on their turn
- Made everyone aware I have no idea how to format indentation when commiting from Visual Studio to Git. Would you mind sharing with me your settings for formatting so my contributions in the future won't look so sloppy (and possibly fix and re-request if this isn't up to par).