LcdSpinBox: check for mouse button in mouseReleaseEvent()

Otherwise we restore things that were never changed when releasing right
or middle mouse button.

Closes #358.
LADSPA/SWH/Vocoder: fixed instantiation on Win32

Due to the nature of DLL files LADSPA plugins need a little extra care
when building for Win32, otherwise they can't be instantiated and won't
be available.

Closes #356.
LcdSpinBox: adopt naming style convention
Freeboy/Gb_Apu: fixed require() statement

Classical off-by-one error.
Revert "Papu: fixed out-of-bounds array access due to too small data types"

This reverts commit ea5f5c4f00eee047c09fe3643d765d376adcc267 as the actual
off-by-one error has been fixed.
Merge pull request #361 from diizy/stable-0.4

SID artwork
Updates to song editor style. Also couple of fixes to SID layout.