Compress/Uncompress data when putting/getting it with swift client

Add the capability of compressing/uncompressing data using swift python client before sending or receiving objects over the network.

Data could be compressed by the client in order to reduce bandwidth usage and server's workload, the server must also verify if the data is compressed, if not do the compression as it does already.

Arguments are to be added to the CLI to support automatic compression and decompression. Compression validation is being coded by another blueprint. The code observes if validation is ok and then perform compression or decompression if needed.

Depends on: https://blueprints.launchpad.net/python-swiftclient/+spec/validate-object-content-encoding