Added Timer Sample

Hello!

Added a simple timer system that I like to use for my games. It's not a true accurate time tracker, but honestly you won't have an accurate timer anyway with most the systems as all PGM is based on frame rates and is subject to pauses in logic. The main reason for a timer is general time of game play that can show on save/load slots. In this sample you have 2 scenes you can transition back and forth from to see the timer always displaying.

The only thing you may consider adding is a hours cap, assuming you want one.