lodash's curry is great and does a lot, but we don't need it all. This
is quite a bit faster.
Currently, it does away with placeholder support.
updeep curry partial call x 9,951,410 ops/sec ±1.61% (62 runs sampled)
lodash curry partial call x 988,949 ops/sec ±1.36% (62 runs sampled)
With u.if and u.is, it was too confusing. Originally I thought that because
u stood for update, it would make sense, but as I add more functions,
I think that was wrong.
