Base model refactor (#810)

* Big upgrades

* WIP: Stash

* Stash, 30 flow errors left

* Downgrade mobx

* WIP

* When I understand the difference between class and instance methods

* 💚

* Fixes: File import
Model saving edge cases
pinning and starring docs
Collection editing
Upgrade mobx devtools

* Notification settings saving works

* Disabled settings

* Document mailer

* Working notifications

* Colletion created notification
Ensure not notified for own actions

* Tidy up

* Document updated event only for document creation
Add indexes
Notification setting on user creation

* Commentary

* Fixed: Notification setting on signup

* Fix document move / duplicate stale data
Add BaseModel.refresh method

* Fixes: Title in sidebar not updated after editing document

* 💚

* Improve / restore error handling
Better handle offline errors

* 👕

app/scenes/CollectionExport.js

@@ -33,7 +33,7 @@ class CollectionExport extends React.Component<Props> {
 
   render() {
     const { collection, auth } = this.props;
-    if (!auth.user) return;
+    if (!auth.user) return null;
 
     return (
       <Flex column>