New design system, GitHub session locking, and documentation

This release is a refinement of our initial release, fixing a number of bugs and adding interaction improvements. The look and feel of the UI was also updated with the start of a new CSS design system based on custom properties. Session locking was added for the live demo and GitHub backend so multiple devices/browsers/tabs don't clobber changes of each other. Documentation also got an upgrade with the start of a full guide on the website.

Bugfixes

• Autosave error when switching between devices #32
• Deleting a node doesn't delete child nodes #25
• Hitting return should produce a new node directly below the above node #29
• TypeError exception when switching back from new panel #65
• Support emojis #52

Enhancements and Chores

• Typography and layout improvements to application #37
• Add keyboard shortcut to move nodes up or down #28
• Prevent backspace to delete if there are child nodes #15
• Allow renaming the workspace #23
• Clicking outside of the search bar/command palette should close it #48
• Workspace/workbench separation #39
• Add API docs #34
• Set up versioned library bundle #41
• Allow backspace to delete an empty child node #53
• Save last location on reloads #54
• Hide buttons to move a panel up/down #49