Rename createTemporary to dangerouslyCreateAndAdd

Class: `ConversationController`.

This function should not be used in application code as it creates potentially
invalid `Conversation` instances in our global conversation collection. We keep
making it available for testing purposes.

test/views/message_view_test.js

@@ -2,7 +2,7 @@ describe('MessageView', function() {
   var convo, message;
 
   before(function() {
-    convo = ConversationController.createTemporary({id: 'foo'});
+    convo = ConversationController.dangerouslyCreateAndAdd({id: 'foo'});
     message = convo.messageCollection.add({
       conversationId: convo.id,
       body: 'hello world',