game-board-view: Don't assume the current event is a button press When using a touchscreen, the current event will be of type TOUCH_BEGIN rather than BUTTON_PRESS, and this populates different fields in the GdkEvent union.
The GtkGestureMultiPress has already processed the click/touch/etc. event and derived x and y coordinates from the raw data, so all we need to do is to round them to an integer.
