qsynth: update from 0.3.6 to 0.3.8

http://monitor.nixos.org/buildlog?outpath=%2Fnix%2Fstore%2Fycg9bkl40sch06kcyjvmnmkxq5mas9p6-qsynth-0.3.8
qtractor: update from 0.5.4 to 0.5.12

http://monitor.nixos.org/buildlog?outpath=%2Fnix%2Fstore%2Fyaq7iknwr79xwrmc4igrs3ygdy61ryjl-qtractor-0.5.12
samplv1: update from 0.3.5 to 0.3.6

http://monitor.nixos.org/buildlog?outpath=%2Fnix%2Fstore%2Fdgrhrqf4j0q0601fgh81bhzkcgj7h4b0-samplv1-0.3.6
synthv1: update from 0.3.2 to 0.3.6

http://monitor.nixos.org/buildlog?outpath=%2Fnix%2Fstore%2Fr5rfpb9zn3pa8yhxfz5d5ngqqj6n6mgg-synthv1-0.3.6
hydrogen: update from 0.9.5 to 0.9.5.1

http://monitor.nixos.org/buildlog?outpath=%2Fnix%2Fstore%2Fxvg8py63xnwyyqmaws7n310l423xbp9h-hydrogen-0.9.5.1