Add u.is

[aaronjensen]

Works like u.in but simply returns true or false if the predicate is met:

u.is("a.b", 3, { a: { b: 3 } }); // => true
u.is("a.b", 2, { a: { b: 3 } }); // => false
u.is("a.b", isEven, { a: { b: 3 } }); // => false

predicate can be a value or a function. If it's a function, invoke it and use the return value.
path can be a string or an array, just like u.in.

I may have gotten the order of the arguments of u.in and u.is wrong... wondering if value should be first...

[aaronjensen]

5c0855b