Create contact by number with no country code or +

Search box finds or creates a conversation given a phone number in
local (to the user's region) or international format.

Previously you had to enter e164 format to set up the conversation
correctly.

If the number is not valid, do not open the conversation.

TODO: user feedback on invalid numbers.

// FREEBIE

js/views/conversation_search_view.js

@@ -66,9 +66,17 @@
         },
 
         createConversation: function() {
-            this.$el.trigger('open', this.new_contact_view.model);
-            this.initNewContact();
-            this.resetTypeahead();
+            var conversation = this.new_contact_view.model;
+            var error = conversation.validate(conversation.attributes);
+            if (!error) {
+                ConversationController.findOrCreatePrivateById(
+                    this.new_contact_view.model.id
+                ).then(function(conversation) {
+                    this.$el.trigger('open', conversation);
+                    this.initNewContact();
+                    this.resetTypeahead();
+                }.bind(this));
+            }
         },
 
         open: function(e, conversation) {