Implement more complex join patterns

[Dtenwolde]

Add support for more complex join patterns, such as combining the result of a quantified path pattern with more joins
For example:

MATCH o = ANY SHORTEST (p:Person)-[w:knows]-> {1,3}(p2:Person)-[i:hasInterest]->(t:Tag)

Which is equivalent to

MATCH o = ANY SHORTEST (p:Person)-[w:knows]->{1,3}(p2:Person), 
					(p2:Person)-[i:hasInterest]->(t:Tag)

Which can be broken down into two subqueries. The result of this is joined on the common node, which is (p2:Person) in this case.

[Dtenwolde]

Implemented as of #69