Added fast functions for checking edge uniqueness. This will help
improve performance for MATCH queries with paths longer than 3 but
less than 11. The normal edge uniqueness function will deal with
any path 11 and over.

    modified:   age--1.6.0--y.y.y.sql
    modified:   sql/agtype_graphid.sql
    modified:   src/backend/parser/cypher_clause.c
    modified:   src/backend/utils/adt/age_vle.c