google/cayley — pull request #103 by barakmich (2014-08-06 19:44:22+00:00)
Title: Fix Materializer iterator

@pbnjay called it -- I'm already using a slice for a Token (in LevelDB). A little interface checking much like we do in graph.Next() and we're off to the races.

So this fixes that. FWIW, my (short) LevelDB integration test now works nicely:
```
benchmark old ns/op new ns/op delta
BenchmarkNamePredicate 3711980 3762244 +1.35%
BenchmarkLargeSetsNoIntersection 1053716200 359610220 -65.87%
BenchmarkNetAndSpeed 118463512 43387005 -63.38%
BenchmarkKeanuAndNet 36273657 29388081 -18.98%
BenchmarkKeanuAndSpeed 53150229 36212122 -31.87%
```

Which are probably more realistic numbers than the memstore ones. But still a good thing overall!