- Adding Private Groups list ("More groups")
- Bug fixed: rocketchat_subscription "open" flag is now updated when user reopens a given room

Changed /usersettings to /account; fixed user language not being selected on language selecion; fixed menu not closing on mobile after clicking a link. Closes #465

Move user settings to new directory; keep old userSettingsFlex for later reference as userSettingsFlex2

private group and channel.  Check for illegal name for private group.

- Use il8n for error messages
- Add il8n english error message for duplicate channel/private group
  name
- Add illegal name serverside check to createPrivateGroup method
- Add logic to handle different error types on privateGroupsFlex page