modify tile size

Hi,

thanks a lot for your fantastic tool :)
i'd like to use a different type of tiles : a 30 grid similar to the ink scape one like this :
http://imgur.com/6AyUnhf

Is it possible ? How can I "set" the engine to use different shape of tiles for eveyrthing ? (movement, detection and so on)

Thanks in advance for your answer :)

Best regards.