Support Arrow reading nested types

[Jolanrensen]

Currently Arrow reading does not support nested types, such as for StructVector or
ListVector (which we don't support at all). We might need some recursive function, such as here for Maps in Spark to perform the type mapping, or at least let DataFrame infer the types like with a call to inferType().

I'm not sure whether Arrow allows for arbitrarily nested Lists.

But it seems like ListVector.field.children[].type is available ;)

For writing, see #271

[Jolanrensen]

see #536