nimbus-devtools 0.4 release

[Beth Rennie]

Good afternoon experimenters!

We've got a new release of nimbus-devtools hot off the presses. This version has a tonne of new features, including:

* integrating Experimenter with about:messagepreview to instantly preview supported messages by clicking the preview icon:

* open and evaluate targeting expressions in nimbus-devtools directly by clicking the debug button: 

* opt-in to experiments for testing with a single click -- no more copying and pasting about:studies links

You can view the full changelog and download the latest version on GitHub: https://github.com/mozilla-extensions/nimbus-devtools/releases/tag/release%2Fv0.4.0

Please file all bugs you find on GitHub: https://github.com/mozilla-extensions/nimbus-devtools/issues

Happy experimenting!

-- Beth