InstrumentFunctions: fix base note playback in chords

As of 6650dd356dbdd08739ad69153b0c7020e39787b9 base notes are not played
anymore when chords are enabled. Therefore create a separate NotePlayHandle
for the base note like we do for all other notes in the chord.
Fix globalautomationvalueat and coding style
Merge pull request #748 from diizy/master

Fix globalautomationvalueat and coding style
Drag-and-drop support for VST, SF2
Random wave first commit, pixmap button defect
ZynAddSubFX: imported current head

Imported current head of LMMS-specific ZynAddSubFX source code.

HEAD: c38c705ea40914f6bd63f799ab8dad91411a93c0
Gui button fix, test backward compatibility
SampleBuffer: fix amplification
Random graph approximation and cleanup
SampleBuffer: amplify in post
Code simplifed
FxMixerView: prevent mixer from being loaded with improper send buttons which cause crashes when clicked, fixes #766
New NES instrument
New NES instrument
Nes: fix sweep
Merge pull request #771 from diizy/nes

NES instrument
Merge pull request #768 from diizy/master

FxMixerView: prevent mixer from being loaded with improper send buttons ...
Merge pull request #761 from zonkmachine/random-wave-2

Random wave for instrument plugin LFO
Merge pull request #758 from grejppi/master-samplebuffer

SampleBuffer: fix amplification
Merge pull request #752 from tresf/master

Drag-and-drop support for VST, SF2