toggleHelp( override ) {

		if( typeof override === 'boolean' ) {
			override ? this.showHelp() : this.close();
		}
		else {
			if( this.dom ) {
				this.close();
			}
			else {
				this.showHelp();
			}
		}
	}
Open or close help overlay window.

@param {Boolean} [override] Flag which overrides the
toggle logic and forcibly sets the desired state. True means
help is open, false means it's closed.