Added new menu in the UI for key mapping in index.html.
Modified default.css to correct the size of the background in the menu.
Added setKeyMappingMenu() and setKey(event) functions to ui.js, to respectively create the menu and send the event that a new key is wanted for an action.
Added the setKey command to the setMessageTriggers() function in trigger.js to match the new UI elements.
Added the mapKeyToControl(action,keyCode) function to trigger.js, to add the new wanted key (given by keyCode) to an action, remake the window.controls object and update the events handler by redoing proliferate.