Add support for Symfony NegativeOrZero Constraint

manual test case:
add a NegativeOrZero constraint to field_test_int, save it.

if populate field_test_int 10, get an error message.

if populate field_test_int 0, no error message.
if populate field_test_int -10, no error message.

Automatically closed - issue fixed for 2 weeks with no activity.