Replaced python execfile with python 3 compatible code
Replaced python execfile with python 3 compatible code

Change-Id: Iffa32b25a6bf541881756cfef0be0978008643f3

hendradarwin/SimpleITK,hendradarwin/SimpleITK,hendradarwin/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,blowekamp/SimpleITK,kaspermarstal/SimpleElastix,blowekamp/SimpleITK,kaspermarstal/SimpleElastix,SimpleITK/SimpleITK,SimpleITK/SimpleITK,InsightSoftwareConsortium/SimpleITK,blowekamp/SimpleITK,richardbeare/SimpleITK,kaspermarstal/SimpleElastix,richardbeare/SimpleITK,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,richardbeare/SimpleITK,SimpleITK/SimpleITK,hendradarwin/SimpleITK,InsightSoftwareConsortium/SimpleITK,richardbeare/SimpleITK,hendradarwin/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,SimpleITK/SimpleITK,blowekamp/SimpleITK,hendradarwin/SimpleITK,SimpleITK/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,hendradarwin/SimpleITK,kaspermarstal/SimpleElastix,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,blowekamp/SimpleITK,kaspermarstal/SimpleElastix,hendradarwin/SimpleITK,SimpleITK/SimpleITK,InsightSoftwareConsortium/SimpleITK,richardbeare/SimpleITK,InsightSoftwareConsortium/SimpleITK,InsightSoftwareConsortium/SimpleITK,SimpleITK/SimpleITK,SimpleITK/SimpleITK