• Adds a Cell Tools sidebar that allows you to edit notebook cell metadata. #1586.
• Adds keyboard shortcuts to switch between tabs (Cmd/Ctrl LeftArrow and Cmd/Ctrl RightArrow). #1647
• Upgrades to xterm.js 2.3. #1664
• Fixes a bug in application config, but lab extensions will need to be re-enabled. #1607
• Numerous other bug fixes and style improvements.