add names to conversation view and set header styles

Change-Id: Ic34b2cea754a5a82224a9fbf158b0126c7e44a5e
diff --git a/client/src/locale/en/translation.json b/client/src/locale/en/translation.json
index 19ddf26..a7de038 100644
--- a/client/src/locale/en/translation.json
+++ b/client/src/locale/en/translation.json
@@ -1,4 +1,14 @@
 {
+  "conversation_title_one": "{{member0}}",
+  "conversation_title_two": "{{member0}} and {{member1}}",
+  "conversation_title_three": "{{member0}}, {{member1}} and {{member2}}",
+  "conversation_title_four": "{{member0}}, {{member1}}, {{member2}}, +1 other member",
+  "conversation_title_more": "{{member0}}, {{member1}}, {{member2}}, +{{excess}} other members",
   "message_swarm_created": "Swarm created",
-  "message_user_joined": "{{user}} joined"
+  "message_user_joined": "{{user}} joined",
+  "message_input_placeholder_one": "Write to {{member0}}",
+  "message_input_placeholder_two": "Write to {{member0}} and {{member1}}",
+  "message_input_placeholder_three": "Write to {{member0}}, {{member1}} and {{member2}}",
+  "message_input_placeholder_four": "Write to {{member0}}, {{member1}}, {{member2}}, +1 other member",
+  "message_input_placeholder_more": "Write to {{member0}}, {{member1}}, {{member2}}, +{{excess}} other members"
 }