Multi-document management (create new document; tab switching) (#210)

* Multi-docs WIP

* Change to number

* Add new document and switch documents

* Remove keybind for previous document. Change keybind for next document.

* Switch documents by clicking tabs

* Remove keybind for previous document. Change keybind for next document.

* multi-docs

* Update package-lock.json

* Hook up File>New to add new document

* Remove console logs and empty lines. Start new documents from 2 instead of 1.

* Fix formatting

client/web/wasm/src/wrappers.rs

@@ -123,6 +123,7 @@ pub fn translate_key(name: &str) -> Key {
 		"backspace" => KeyBackspace,
 		"alt" => KeyAlt,
 		"escape" => KeyEscape,
+		"tab" => KeyTab,
 		_ => UnknownKey,
 	}
 }