#9 Regression (test.sng) fails with libpng 1.7.0beta89

[Thomas Henlich]

When linking with libpng 1.7.0beta89, the following fails:

>sng test.sng
libpng error: gamma value does not match sRGB
test.sng:23: libpng croaked

The same works without error with libpng 1.6.37

After changing line 13 of test.sng to

gAMA: {0.45455}

the test works without error.