Gpredict rotator compatibility

[cameronbosnic]

Having rig and rotator control working through hamlib should be enough to allow automation of nyansat ground stations. (gpredict, satnogs, custom solutions)

Gpredict uses rotor control through rotctld (part of hamlib).

There are already some rigcontrol solutions available for rtl-sdr to automate frequency selection depending on which software is being used.