correction to quick save and load feature

Alt+S is already in use for toggle sound so changing the quick save and
load shift + Alt + S and shift + Alt + L
Merge pull request #97 from MarkL1961/keypresses

correction to quick save and load feature
Adds a sound to taking a screenshot

This will add the sound of the camera click when taking a screenshot
(Ctrl + S)
Merge pull request #112 from MarkL1961/Screenshot-sound-effect

Adds a sound to taking a screenshot