2014-05-06 Version 2.1.0

	Now works with underlying types that support #[] but not #fetch.

2014-04-16 Version 2.0.1

	Added documentation to the module overview specifying the
	requirements for supporting alternate underlying data types
	(i.e. other than Array or Hash). No other changes.

2014-03-21 Version 2.0.0

	XKeys can now be used with data types other than array or hash
	(as long as they support array- or hash-like interfaces).

	New custom nodes can be generated by defining an #xkeys_new
	method. The method is responsible for adding XKeys extensions to
	the new node as needed/desired.

	See Sarah::XK in gem sarah-xk for an example.

	Using :[] (push mode) as the first of multiple keys now works
	correctly.

2013-07-25 Version 1.0.1

	The auto-indexing array key for set has been changed from nil to
	:[] in order to support nil keys (e.g. in case a NULL value from a
	database field is being used as a nil key).

	Get and set now have compatible syntax so that you can use ||=:
	root[key1, ..., keyN[, option_hash]]
	root[key1, ..., keyN[, option_hash]] = value

	root = {}.extend XKeys::Hash
	root[:top, :[], :[] => false] ||= 'just because'
	# root => { :top => { :[] => 'just because' } }

	Note that a leading nil is no longer ignored on get. Use
	array[int1, int2, {}] to avoid array[start, length] slice
	interpretation.

	Option :raise => true raises a KeyError or IndexError on a missing
	value. Option :raise => *parameters raises the specified exception,
	e.g. :raise => RuntimeError or :raise => [RuntimeError, 'SNAFU'].

	The :else option defaults to nil on get. Use :raise to force an
	exception.

2013-07-08 Version 0.0.2

	Packaging and documentation cleanup.

2013-07-08 Version 0.0.1

	First release.