clarifying ssn issue raised in f2f

I mentioned a confusing change (one of those last minute changes we were looking over) here: https://github.com/w3c/sdw/commit/6d146e4eaee757255be79cc9651944554fd6dcf5

It was not a problem with issue-45 as I thought. It was, instead the removal (commenting out)  of an explanation of a change to SSN in the section titled "
"Developments since the initial 2009 publication of SSN" , in particular about the movement of Sensor.

This should not have been commented out.
--Kerry