Fix selecting a tile since cairo 1.17.8
cairo 1.17.8 includes a fix for out of range coordinates [1] which exposed a problem with the values used to translate the context in GameView.find_tile().
[1] 47a21c6e3 ("Clamp path coordinates", 2022-05-15)
Fixes #37 (closed)
translation problem first identified in https://bugs.gentoo.org/904476#c0.
Edited by Chris Mayo