Make _keyHandler and _valueHandler private.

* And rename to remove leading underscores.
Unnecessary parens.
Whitespace.
Make isObject check for !isArray()

* Talk to me and Zach about modules and binding and some of the other nuggets we discussed in our 45 minutes conversation about 3 lines of incidental code.
No need to make renameProperty live in Object.

* requiring utils had the side effect of putting renameProperty on Object.  Best to avoid side effects when requiring.
* Best to avoid putting things on built-ins unless absolutely necessary.  Makes code that uses your lib harder to reason about.
Whitespace.
Typo.
Be clear that interpolators do not support args.

* The docs implied that interpolators could accept args.  They cannot.
* randomString test did not test for case where arg used.
* valueHandler did not pass args along to interpolators.
* Updated docs and randomString()
Suggestion for improvement.