Allow multiple simultaneous file uploads to remote destinations

Since the process of transfering files to Amazon S3 is slow. And backups having to transfer large amounts of data to Amazon S3. The cpbackup transporter rtakes for ever to copy the backup to Amazon S3.

According to http://improve.dk/pushing-the-limits-of-amazon-s3-upload-performance/ you can speed up the transfer rate by uploading multiple files simultaneously.

Adding a setting to specify the number of "tasks" / files it may process at a time would allow us to speed up the uploads.

If this defaults to 1 it would not affect normal users and the users that need to can experiment to find the optimal number between upload speed vs the capacity so that it does not influence the normal operations