Add SV FILTER Versions

[eclab]

SV FILTER has had two versions: 1.1 and 1.2.

My 1.1 SV FILTER is quite dark and has very, very limited CV range.

The 1.2 SV FILTER has a trimpot which lets you adjust the top end of the filter cutoff to be much brighter; it also has a much broader range. My 1.2 SV FILTERs are much brighter and more usable.

I have asked Robert about the 1.2 trimpot but haven't gotten a response back yet on it. It'd be helpful to include this information in the Wiki, particularly as my two 1.2 SV FILTERs had their trimpots set to different values and had different brightnesses as a result. :-(

[eclab]

Robert has gotten back with me and agrees that the purpose of the 1.2 trimpot is to adjust the filter cutoff range. By default it's set to nearly maximum: I think it's better at maximum.