Object data and contains and in membership operators

[jg-rp]

The non-standard contains and in membership operators currently work for any sequence.

python-jsonpath/jsonpath/env.py

Lines 551 to 554 in 880c123

	if operator == "in" and isinstance(right, Sequence):
	return left in right
	if operator == "contains" and isinstance(left, Sequence):
	return right in left

We should change that so they work for any container (any mapping is a container).

[jg-rp]

Closed by #63.