feature: tx should support query methods

[ChandlerBent]

I wrote some unit test and begin tx. I need to query node after I create it on tx.
I will rollback data on unit test end.

Example: match, match_one, nodes, relations

class Transaction(object):
    ...

    @property
    def nodes(self):
        return NodeMatcher(self)

    @property
    def relationships(self):
        return RelationshipMatcher(self)

    def match(self, nodes=None, r_type=None, limit=None):
        return RelationshipMatcher(self).match(nodes=nodes, r_type=r_type).limit(limit)

    def match_one(self, nodes=None, r_type=None):
        matches = self.match(nodes=nodes, r_type=r_type, limit=1)
        rels = list(matches)
        if rels:
            return rels[0]
        else:
            return None

This code is work.