Marc, Michael, Yuhang

Today we added the PR pointing loop to medm.

It is basically a copy & paste of BS pointing loop except that we had to change the pitch gain sign.

We could close the loop and things seem stable.

On medm there are now 2 buttons to close pointing with feedback on either BS or PR.

However, as pointed in entry 2493 PR is drifting more than BS so closing the pointing loop on PR instead of BS should be useful for long term stability.