RFC Compiler options should be grouped under a thrift key

[dantswain]

Right now thrift_files and thrift_output have to go right in the project config's root namespace. I think it would be cleaner if they were nested under a thrift key:

def project do
  # ..
  thrift: [
    thrift_files: Path.wildcard("thrift/*.thrift"),
    thrift_output: "gen-lib"
  ]
end

Doing this it might make sense to change the names of the parameters to not have a redundant "thrift_" prefix.

By way of prior art: This is the way dialyxir works, and it's fairly intuitive and unobtrusive.

[jparise]

That's an interesting idea. I think there's prevent both ways (with the erl* and elixir* keys), but this could be a nice improvement.

I can look into this in a couple of weeks. It would be nice to hear any other thoughts in the interim.

[dantswain]

It looks like the changes would be pretty easy to make and I'd be glad to do it if we get agreement.

ExDoc also uses this approach (docs: []). Hex sort of uses this approach with the package: [] key.

[scohen]

I'm a fan, as long as we don't stutter thrift: [files: ...] as opposed to thrift: [thrift_files:...]

[jparise]

Implemented by #197