Testing the bus mixer and the waveshapers

Not much to say really, the bus mixer works perfectly with VCAs, switches and I2C, though I haven't checked the polarities and gain.

Oh, and for future testing: When leaving out the VCAs and connecting input to output on the FX VCAs - the input 47k resistor and the output 47k resistor will act as a resistor divider. Thus, the output is half of what would be expected, this threw me off a bit before I realised what was going on.

The waveshapers also seem to be working fine - I only tested with a non-symmetric triangle wave from my function generator, but all trim pots and CVs seem to work as they should.

These were the ones I most expected to work. Next up are the filters, I don't particularly look forward to testing those...