todo_jeremyz

core classes :
 - Logger               done
 - Object               done

basics classes :
 - ADSR                 done
 - Note                 done
 - Sample               done
 - InstrumentLayer      done
 - Instrument           done
 - InstrumentList       done
 - Drumkit              done
 - Pattern
 - PatternList
 - Song

remove old classes :
 - LocalFileMng
 - SoundLibrary

rework :
 - Preferences rework

GUI :
 - use new InstrumentList capabilities
 - SampleEditor
   - use only SampleLayer index as constructor parameter
   - __sample = Sample::load( path )
   - __current = Sample::load( path, loops, rubber, velocity, pan );
   - add reset butto(s)
   - must update sample view when finished
   - compute rubberband parameters, see Rubberband declaration in sample.h
   - compute velocity and pan envelope, see apply_velocity and apply_pan in sample.cpp

fix : src/gui/src/SampleEditor/SampleEditor_UI.ui: Warning: Z-order assignment: 'horizontalSpacer[_2]' is not a valid widget