Changed environment enum to use NS_ENUM.
Changed environment enum to use NS_ENUM.

Eynaliyev/Atlas-Messenger-iOS,layerhq/Atlas-Messenger-iOS,InterfaceInc/Atlas-Messenger-iOS,InterfaceInc/Atlas-Messenger-iOS,InterfaceInc/Atlas-Messenger-iOS,Eynaliyev/Atlas-Messenger-iOS,ropik/Atlas-Messenger-iOS,ropik/Atlas-Messenger-iOS,layerhq/Atlas-Messenger-iOS