Test image board

Just a small complementary test to check if image export works.
I have an issue with the export using CAIRO, all these images are blank:
boardTestDisplayImgeCAIRO.eps
boardTestDisplayImgeCAIRO.pdf
boardTestDisplayImgeCAIRO.png
(by using ./tests/io/testSimpleBoard)
Have you also the same ? I will put an issue if you have also the pb... (I have not activated imagemagick perhaps related)