Offsets for motor control

[imyxh]

Hi, I noticed that srt-py wasn't sending the right coordinates to the motor, and fixed them in this commit to my fork: imyxh@ed6d110

I'm curious about the +0.5° that you're doing, and the fact that you send [az,el] relative to the limits. This seems to be incorrect at least for our motor. Is this something that varies across models?

[AlexKurek]

0.5 seems to be to prevent rounding down - a leftover from C. In Python maybe math.ceil() would be better.