added hide and show of screens to dom and game module

dom module uses Sizzle now to remove and add classes to dom elements

game module adds the active class to screens that are active and removes the class from other possible previously active screens
configured and styled first screen: the splash screen
scaling based on em now instead of px
added even handlers for menu and screen submodule for screen information
[css mod] margin removal
[readme] adjusted readme, decided to skip mobile options for now
implemented basic game board and methods
check removes detected chains and moves jewels in gaps down
fill up gaps after chain removal
style change, no more positioning in the top left corner for mobile use. focussing on desktop use for now.