Merge branch 'conn-pool-leak' into develop

* conn-pool-leak:
  Remove set_session, it's no longer used
  Fix integ tests with fileinfo signature changes
  Change signatures to require service/endpoint, not session
  Rename operation to operation_name
Add test infrastructure to check memory usage

Add a single test that verifies memory usage of an upload/download
of a file that triggers multipart upload/downloads.
Fix memory utilization for uploads

A ReadFileChunk is introduced so that we can upload file parts
from a file rather than buffering the entire part in memory.

Also, the etag verification for downloads was chnaged. What we do
instead is calculate the md5 writing the file, and if the md5
verification fails, we delete the file.
Fix failing tests from switch to fileobjs for uploads
Update tests to work with python3