Log when deleting directory.
Add try-catch around shutil.rmtree
Put oai_helper.export in try/catch
Do not fail of step file cannot be deleted
If the XPath throws an error, it did not match
Prevent MemoryError when concatenating large files
Add proper error message when failing the export
Add progress callback for boto
Make percent_cb independant of class
Add re-try block for S3 upload
Add deleting the temp dir in finally block
Further improved error reporting
Include harvest_object when saving errors
Merge pull request #15 from ogdch/temp-folder-issue

Temp folder issue
Use multipart uploads to get rid of S3 timeouts
Implement parallel upload of parts
Add logging statements
Make _upload_part independant from S3 class
Set headers instead of using copy

The copy command does not work for files bigger than 5GB, therefore a
different solution is needed.
Raise exception when upload is incomplete