Modartt updates Pianoteq to v3.5.1

Modartt has updated Pianoteq to v3.5.1.

Changes:

• Fixed VST-specific bug when loading old projects or FXB files in the VST plugin.
• Fixed crash when loading some custom keyboard mappings.
• Slightly improved performance of multicore-rendering on windows.
• Minor adjustment of the damper model. KIViR.ptq also updated.