Added timer display to GUI

A timer that counts down from 60 to 0 is now displayed in the GUI.
Game now ends when timer expires
Fixed Time Remaining and Refactoring

Fixed time remaining so that it is set to 60 each round. Previously it
started counting when the game started and nothing reset it.
For refactoring removed commented out code.
Added check to make sure a checkbox is selected

The game will not try to start unless at least one checkbox allowing a
word length is selected.
TODO:
Add error message if none are selected
Put checkboxes in collection
Put checkboxes in List

The charactersAllowedInWordCheckBoxes List was added that contains all
the checkboxes for different number of characters allowed in a word
checkboxes.
Merge pull request #1 from mickubik/Add-Timer

Add timer