Makes Theme loading resilient

Load theme defined by user, platform according to theme availability.
If no theme available try to fallback on hardcoded themes.
If no luck, spawn Layout so the user see something (ugly but better than fatal
error).

Changes:
* Hard code font size
* No longer user "old browser" (for those who still use netscape4... good luck)

Change-Id: If96e330b3460f53431db891817802ef6b4be2784
Fix aggregates issue in report

Change-Id: I69b091b006ae2e7520ec3d47068ec513b9397c4c
Merge commit 'refs/changes/67/2367/1' of ssh://gerrit.tuleap.net:29418/tuleap into tuleap-stable-master

* ssh://gerrit.tuleap.net:29418/tuleap:
  Fix aggregates issue in report

Change-Id: Ibaa6c8b0976b43fc9d743e0a94ba48b759f45161
Tuleap 6.12.99.91

Change-Id: Ie421584f35704e50286d4dd73cbf08af7471123a
Merge commit 'refs/changes/62/2362/1' of ssh://gerrit.tuleap.net:29418/tuleap into tuleap-stable-master

* ssh://gerrit.tuleap.net:29418/tuleap:
  Makes Theme loading resilient

Change-Id: I698f867afb82859173678c16d33dba905c88fc80
Tuleap 6.12.99.92

Change-Id: I9f31f7b1550c6caed66f6160bf7c9f1a74d9c56a