Hookup ui for marking a conversation important/ not important.

Change-Id: Ic699aa172adccb335d67978abf4c0bd95d958a61
diff --git a/src/com/android/mail/providers/UIProvider.java b/src/com/android/mail/providers/UIProvider.java
index 2331ddc..cccafce 100644
--- a/src/com/android/mail/providers/UIProvider.java
+++ b/src/com/android/mail/providers/UIProvider.java
@@ -193,6 +193,10 @@
          * Whether the account provides help content.
          */
         public static final int HELP_CONTENT = 0x4000;
+        /**
+         * Whether the account provides a mechanism for marking conversations as important.
+         */
+        public static final int MARK_IMPORTANT = 0x8000;
     }
 
     public static final class AccountColumns {