Merge pull request #648 from diizy/master

Interpolation, MemoryHelper - fixes
Merge pull request #651 from diizy/master

Optimizations for Monstro & Watsyn
SongEditor: change middle click to shift+right click, fix #621
Fixed broken delay/reverb on various presets
keep deletion with middle click
Merge pull request #653 from Umcaruje/master-fixpresets

Fixed broken delay/reverb on various presets
Merge pull request #654 from grejppi/master-songeditor

SongEditor: change middle click to shift+right click, fix #621
InstrumentTrack: fix FX channel range

Because it is set to INT_MAX by default and never corrected for
cloned instruments, it could go over the maximum and cause a
segmentation fault.
Merge pull request #658 from grejppi/master-fxrange

InstrumentTrack: fix FX channel range