Disable START n = node(...) in favor of MATCH n WHERE id(n) = ...
Add legacy index hints to the query graph
Build legacy index seek plans
Started fixing tests that use the discontinued start clause to use newer match/id syntax
Updated cypher docs to new syntax without start clause
Change scoping rules for UNION

1) Create a child scope for the LHS and RHS of a union clause.
2) Move the "columns have to be the same" check to semanticCheck.
Merge branch 'start-hints'