feat: add python 3 cmake options
feat: add python 3 cmake options

sunbingfengPI/OpenSFM_Test,sunbingfengPI/OpenSFM_Test,oscarlorentzon/OpenSfM,oscarlorentzon/OpenSfM,mapillary/OpenSfM,sunbingfengPI/OpenSFM_Test,mapillary/OpenSfM,mapillary/OpenSfM,BrookRoberts/OpenSfM,BrookRoberts/OpenSfM,sunbingfengPI/OpenSFM_Test,sunbingfengPI/OpenSFM_Test,mapillary/OpenSfM,BrookRoberts/OpenSfM,BrookRoberts/OpenSfM,oscarlorentzon/OpenSfM,oscarlorentzon/OpenSfM,BrookRoberts/OpenSfM,mapillary/OpenSfM,oscarlorentzon/OpenSfM