[sdk] R1 branch merged into master

Hi everybody,

Just wanted to give a hint that feature/r1 branch of the OpenStackSDK is now merged into the master. While most of the challenging things are now completed the work is not finished yet, but will soon be.

Most important: most of the work is backward compatible, but few things were not. I took care on keeping things working and testing, but there might be side effects that I have not expected. Please let me know if jobs in your projects start failing.

Regards, Artem