BUG: Fix generalized ufunc so repeating labels in one input/output is ok
BUG: Missed case of broadcasting onto core dimensions in gufunc
BUG: Make sure the nditer doesn't complain when 0 broadcast dims
TST: Add test for gufunc scalar case
BUG: Fix bug in gufunc scalar case
TST: Test for a generalized ufunc bug, for zero-sized inputs
BUG: Fix for generalized ufunc zero-sized input case