happo for npm release notes

This major release includes two breaking changes:

• Remove approve/reject feature.
• Require S3 credentials to be specified by environment variables instead of the configuration file. (Thanks @serena-w!)

Changes:

• Rename from Diffux-CI to Happo. All commands and code have been renamed to match.
• Remove dependency on diffux-core gem.
• Loosen dependency on oily_png from 1.2.0 to 1.2.

• Add public_directories configuration that allows files from the consuming repo to be available when taking snapshots. This enables the use of custom font files (thanks @serena-w!).
• Prevent newlines in long directory names.

• Examples that require asynchronicity can now return a Promise instead of relying on the done callback.
• Improved stack traces for errors when running examples (thanks @serena-w!)

This release updates the dependency on Selenium to the latest version. This fixes issues with using diffux on Firefox version 43 and later.

Changes:

• Fixed bug where new examples weren't being uploaded

Changes:

• diffux upload_diffs will now also upload new snapshots created as a result of the last run.

• base64 names are now used to store files, which leads to better review and diff pages https://github.com/diffux/diffux_ci/commit/f41f19cc36e3d22aec02ba51a5a4ab0bdcc1a024

• Made Amazon S3 bucket name configurable
• Small performance improvements

• The command line tool is now called diffux (62988a0)
• No more soft-dependency on React (7f45c08)
• fdefine now works on multiple examples (09007b)
• Improved output while running the command (e7628e2)
• Less window resizing while rendering examples (improves performance! 7bc2839)