Checked the alignment of the 70W beam towards the pre-modecleaner.  After some minor adjustments
things locked up.  The pre-modecleaner servo locked okay but starts oscillating when the servo
gain slider is increased beyond 0 dB.

    The alignment to the reference cavity was also tweaked up.

    The last optic that turns the beam into the ISS photodiode box was replaced with a 30%
reflecting plate beamsplitter, a Thorlabs BSS11.  This reduces the amount of light incident
on the photodiodes without having to dump most of it inside the box.
The beam incident on the quadrant photodiode was re-centred.  The DC output of the
photodiodes was set to ~11.5 VDC.  The intention being that when the ISS is locked, the
locked DC output of the photodiodes will be 10 V, or ~3 mA of photocurrent.