Better OR support for mixed indexes

[davidclement90]

Currently these traversals do not match indexes

g.V().has('age', outside(20, 50))
g.V().has('age', lt(50).or(gte(60)))
g.V().or(__.has('name', textContains('hercules')), __.has('age', inside(20, 50)))

Is-it not the problem of mixed index backends which can handle OR but of the Strategy which do not root theses traversals to mixed indexes.

[pluradj]

@davidclement90 is this a duplicate of #163?

[davidclement90]

Yes I did not find it when I search.
I close this and I change the PR description.