Update ser.py

Implementing ThreadPoolExecutor approach in uploading images
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Merge branch 'live' of github.com:OlegYarosh/pin into live
Merge branch 'live' of github.com:OlegYarosh/pin into live
Merge branch 'live' of github.com:OlegYarosh/pin into live
Merge branch 'live' of github.com:OlegYarosh/pin into live
Update ser.py

Adding missing imports
Update ser.py
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Merge branch 'live' of github.com:OlegYarosh/pin into live
Merge branch 'live' of github.com:OlegYarosh/pin into live
Update media.py

Extending function for storing images on S3 using ThreadPoolExecutor.
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Update media.py
Update media.py

New release of media.py
Update media.py

Update comments of store_image_from_filename function.
Update media.py

Comment update media.py
Update ser.py
Update ser.py

Revert changes of ser.py