Rewrite instant messaging screen

- HyperLink activated - YAY
- No more bubble size problem
- Username and date are now in an italic footer
- Username and date display are now saved in user preferences
- Remove sender avatar from right message as it's kind of
unnecessary

* Need LRC patch connecting message engine stuff : 4059 *

Change-Id: Id1adb1e96d99eb02a2c1e85a066dbbdc3e87cdc0
Tuleap: #601
Tuleap: #290
diff --git a/settingskey.h b/settingskey.h
index 0620901..def8286 100644
--- a/settingskey.h
+++ b/settingskey.h
@@ -24,6 +24,8 @@
 constexpr static char autoAnswer[] = "autoAnswer";
 constexpr static char savedSize[] = "savedSize";
 constexpr static char savedPos[] = "savedPos";
+constexpr static char imShowAuthor[] = "imShowAuthor";
+constexpr static char imShowDate[] = "imShowDate";
 }
 
 #define accountAutoAnswer(A) (A+SettingsKey::autoAnswer)