Merge topic 'SIMPLEITK-400_UpgradeTowardsITK_4.4'

482712b Upgrading ITK superbuild to ITK 4.4.0
99720b3 ENH: updating ITK 4.4rc1
767a6ee Upgrading superbuild ITK version to 4.3.2
Merge branch 'master' into next

Change-Id: I26ed526fb7853a47b23713b70f093506bd248177