Change all g_test_init calls in the testsuite to avoid the macro, so they work regardless of G_DISABLE_ASSERT.
Adapt all our tests and examples to the new initialization api.
Don't try to paint onto an error surface. This happens for example when gdk_cairo_set_source_pixbuf() is called with a pixbuf that is too big for Cairo to handle. Spotted by Christian Boxdörfer
