Draft patchset and change visibility in UI

If a patchset is a draft, adds a (DRAFT) label next to the revision
(or gitweb link if it exists). If a change is a draft, adds a (DRAFT)
next to the subject and changes the status appropriately.

Change-Id: Ib84ccc2aff9feebc203424a620e2c4b7975ac000

gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeConstants.java

@@ -21,6 +21,7 @@ public interface ChangeConstants extends Constants {
   String statusLongSubmitted();
   String statusLongMerged();
   String statusLongAbandoned();
+  String statusLongDraft();
 
   String changesRecentlyClosed();
 
@@ -140,10 +141,12 @@ public interface ChangeConstants extends Constants {
   String pagedChangeListPrev();
   String pagedChangeListNext();
 
+  String draftPatchSetLabel();
+
   String reviewed();
   String submitFailed();
   String buttonClose();
 
   String buttonDiffAllSideBySide();
   String buttonDiffAllUnified();
-}
+}