This fixes segfaults when something goes wrong during
init, but the test keeps going anyway.
Except for test-easing and test-picking, these were fixed by
sed magic:
sed -i -s -e "s/clutter_init \?(&argc, &argv)/\
if (clutter_init (\&argc, \&argv) != CLUTTER_INIT_SUCCESS)\n\
return 1/" tests/*/*.c
http://bugzilla.clutter-project.org/show_bug.cgi?id=2574
Both ::drag-begin and ::drag-end have a "button" argument - even though
we assume internally, and externally, that dragging can only be the
result of a primary button operation.
