FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/level-errors/test.js

@@ -0,0 +1,20 @@
+var test = require('tape')
+var errors = require('./')
+
+test('all errors are instances of LevelUPError', function (t) {
+  var LevelUPError = errors.LevelUPError
+  var keys = Object.keys(errors)
+
+  keys.forEach(function (key) {
+    t.ok(new errors[key]() instanceof LevelUPError)
+  })
+
+  t.end()
+})
+
+test('NotFoundError has special properties', function (t) {
+  var error = new errors.NotFoundError()
+  t.equal(error.notFound, true)
+  t.equal(error.status, 404)
+  t.end()
+})