Random floats and doubles implemented
Added depth to sf::Transformable
Fixing typo in random double function

Had the double random(double) returning a float in commit
01208081875fa0992e1628dd79229a85f2e03bf1. Fixed.
Fixed const void

Commit e50ed3c79a8b4c2a8e2354b4487f13618ece1e2f declares the setDepth
function as constant. Fixed here.
TGE::Game::draw updated for depth

Game::draw now takes depth into consideration when drawing 2D objects onto the screen.