- Added icon-button UI code for the menubutton
- Upgrade to React 16 to allow non-standard attrs, such as `tooltiptext`
to support XUL tooltips
- Add i18n support for React UI elements
- Update tests for reactified tag selector
* Use mocha, chai & sinon from the npm. As of sinon 2.0
sinon-as-promised is no longer required so it is removed
* Tweak code to re-use the same loader with the same environment
throghout the code
* Introduce browserify step for testing tools that only provide
node-compatible libraries (sinon, chai-as-promised)
* Introduce copy step for test data to resolve multiple issues with
tests depending on files not being symlinks
* Re-introduce custom implementation of setTimeout to resolve issues
with few tests
* Re-introduce custom Bluebird Promises config & monkey patch
