Digital-Scratch v1.6.1

• Features:
  • Novation Dicer: pad 5 (cue point mode) restart the track (#113)
• Upstream updates:
  • update libkeyfinder to v2.1.0 (#114)
• Motion detection engine (libdigitalscratch):
  • improve signal frequency detection using IIR filter (#115)
• Coding:
  • memory allocation
  • API dependency
  • cppcheck suggestions