Fix second problem of issue 338 by truly recalculating the new center from the bbox
Fix second problem of issue 338 by truly recalculating the new center from the bbox

ryanramage/svg-editor,ryanramage/svg-editor,trentmillar/ddp-level-editor,ryanramage/svg-editor,trentmillar/ddp-level-editor,trentmillar/ddp-level-editor