Displays burndown icon

Change-Id: Ib671fec7b06494d94c5a4a2677b495fdc3f7133a
Merge commit 'refs/changes/50/250/2' of http://gerrit.tuleap.net/tuleap into stable

* http://gerrit.tuleap.net/tuleap:
  Displays burndown icon
This is Tuleap 5.10.99.2