Handle unions more elegantly #43
Description
There's a recently-added implementation of XDR/JSON in Go from David Mazieres that you can find here. It does something cool, which is it uses the name of the XDR union discriminant instead of the _type variable in the output. Since the discriminant variable is part of the union, it's not possible to have a name collision between the discriminant variable name and one of the members of one of the union. This seems like a good call!
It'd also be great in general to make the two implementations match, picking the best features of each.