Version 0.7.0

Breaking changes
================

* The `iron-handlers` feature now depends on Iron 0.5
  ([#30](https://github.com/mhallin/juniper/pull/30)). Because of
  this, support for Rust 1.12 has been dropped. It might still work if
  you're not using the Iron integrations feature, however.

New features
============

* Input objects defined by the `graphql_input_object!` can now be used
  as default values to field arguments and other input object fields.