Changed the test:unit pattern to grab additional spec files. [ci skip]
Simplified Array type checkinging.

Removed the #array_like? method of the TreeInterpreter. Not planning to
support Enumerable as too many types in ruby are Enumerable without
behaving like an array or list.
Added support for searching over hash-like objects.

You can now search over hashes with string or symbolized keys.
Also supported are Struct objects.