add more s3 wrapper helpers for aws-sdk in export base class
add more s3 wrapper helpers for aws-sdk in export base class

mkoon/gradecraft-development,UM-USElab/gradecraft-development,mkoon/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,mkoon/gradecraft-development,UM-USElab/gradecraft-development