ADD: Subtraction of Size objects.
ADD: Subtraction of Size objects.

cbeck88/cegui-mirror,RealityFactory/CEGUI,arkana-fts/cegui,cbeck88/cegui-mirror,arkana-fts/cegui,cbeck88/cegui-mirror,arkana-fts/cegui,RealityFactory/CEGUI,arkana-fts/cegui,arkana-fts/cegui,RealityFactory/CEGUI,cbeck88/cegui-mirror,RealityFactory/CEGUI,cbeck88/cegui-mirror,RealityFactory/CEGUI