Here's one option for making working with labels easier: Right now we have for example `Graphs.outneighbors(meta_graph::MetaGraph, code::Integer)` and `outneighbor_labels(meta_graph::MetaGraph, label)`. Maybe we could have a general pattern where we add a `_labels` suffix to a `Graphs` function to make it work with labels instead of code? We could then have a `@labels` macro that attaches the `_label` suffix to all surface-level `Graphs` function calls?