present validation is not as general as the name implies

[ryantm]

I think that the current present validation should be renamed to string-present and that present be changed to a validation that only checks if a map contains a key.

[logaan]

I agree. I've been thinking that really I should create namespaces for each type and fill them with validations. I'd also like to better separate predicates that affect scalar values (String, Long, etc) from Associatives. It seems a little wrong to me that Predicate takes a selector. I'm planning on making these changes shortly but am a bit busy at the moment.