Map class optimization => -33% Server Response Time

Change-Id: I999d69f24b775a8b871e4d08cef33382632c3735
Merge commit 'refs/changes/50/950/2' of http://gerrit.tuleap.net/tuleap into tuleap-stable-master

* http://gerrit.tuleap.net/tuleap:
  Map class optimization => -33% Server Response Time

Change-Id: Id5bc424670fe363ef21010645654fdd4bed3d5dd
Tuleap 6.4.99.22

Change-Id: I8f44dee20aa5d5ab640653b499997bf29e3c3f49