neo4j/neo4j — pull request #2288 by systay (2014-04-19 14:44:24+00:00)
Title: Refactoring of LogicalPlan and QueryGraph

A LogicalPlan now has a `solved` field, that indicates the
corresponding QueryGraph that the plan solves.

QueryGraph now only exists in one version - the difference
between Optional and mandatory patterns is seen by where
the QueryGraph is used and not by a different type.