Add Call Button Option
One possibility is to just assign CALL and ENDCALL to a button using different events. However would be a shame to reserve a whole button for just those actions. Instead we also add another option to buttons allowing users to register them as Call Buttons. This meaning that the button will use any regular seleted action (or default) as long a there is no phone activity and then assign it to CALL or ENDCALL whenever the phone is ringing or there is an active conversation.