allow copy from/to to operate on s3 without access credentials
Merge pull request #950 from crate/m/aws_no_credentials

allow copy from/to to operate on s3 without access credentials
abort merge on reduce node if search threadpool is exhausted
prepare release 0.40.0
Merge tag '0.40.0'
cleaned up changelog for release 0.40.0
fix String.format() exception in SQLTypeMappingTest