Partial merge of develop to experimental

Does not include #2336 as the file has been moved out from underneath it:
will do this separately

src/BasePlatform.js

@@ -3,6 +3,7 @@
 /*
 Copyright 2016 Aviral Dasgupta
 Copyright 2016 OpenMarket Ltd
+Copyright 2018 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -105,11 +106,6 @@ export default class BasePlatform {
         return "Not implemented";
     }
 
-    isElectron(): boolean { return false; }
-
-    setupScreenSharingForIframe() {
-    }
-
     /**
      * Restarts the application, without neccessarily reloading
      * any application code