WIP: trying to use TitanQuery for predicates; nothing works
Revert "WIP: trying to use TitanQuery for predicates; nothing works" for now

This reverts commit 1a3710a51e84043b4828b7fd5ef2f1840ddc3088.
Introduced temporary graph type (will use schema for that); removed PredicateType; added implicit conversion for using edges as empty predicates on them
Added query syntax op; made titan evals independent from the graph; added functor reexports
Added index restriction on predicates and the corresponding syntax method with a check
Added explicit uniqueness setting for composite indexes; improved schema tests
Added indexOnly label constraint for composite indexes
Added dependency of the query out-container on the index uniqueness
Added inV/outV steps and evals for them
Removed indexOnly label restriction, because with it graph queries don't use indexes
Added interval condition for query
Changed scala 2.10 version for travis
Another version fix
Merge branch 'feature/predicates' into feature/static-queries