gemoji 3.0.0.rc1

This release removes all of Apple's images from the library. To obtain those images, run the new gemoji extract command on macOS:

gemoji extract public/images/emoji

Other changes are:

• The Emoji.all collection now includes all emoji available in iOS 10.0 and macOS Sierra.
• New Emoji.apple_palette method returns a hash of raw emoji data organized in categories as per Apple's character palette.
• New Emoji::Character fields:
  • description
  • category
  • unicode_version
  • ios_version