FRI 1.11 support

[Chunyu-Jiang]

Hi, thanks very much for your brilliant work! Really simple and neat interfaces.

May I know if pyfri supports FRI1.11? My robot software is 1.11, and I compile pyfri as 1.15, the readout of joint positions are all static, not changing as I set new joint positions. (The command works) I guess it's the software problem.

When I manually set 1.11 in cmakelist.txt, there are compiler errors.

Thanks for your help!