Summary:
^
flipper-server verifies the origin of incoming connections as a way of preventing any host from connecting to flipper.
That's good.
This change expand the list of allowed origins to include localhost:3000 which is the default origin for Electron apps.
Error without this change:
```
Refused socket connection from cross domain request, origin: http://localhost:3000, host: localhost:52342. Expected origins: http://localhost:52342 or http://[::1]:52342 or http://::1:52342. Expected hosts: localhost:52342 or [::1]:52342 or ::1:52342
```
Reviewed By: passy
Differential Revision: D36440363
fbshipit-source-id: 883cadb49f245bca5d0a53a4f58c08cf45dd0189
aca1aca29c