PLUGIN: Applied coding style on Juce-generated files

- Added Licence text

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
PLUGIN: added missing include

It was required for Juce Midi stuff.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
STYLE: Various minor style fixes.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: style checking now done on juce-generated files

These have the extension ".cpp" (and they will keep it,
for consistency's sake across Juce generated files).

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
PLUGIN: Now using a juce piano roll component

It handles mouse, keyboard as well as any actual Midi input,
and provides a simple visual feedback.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
COMMON: Changed output range to be more "music standard"

Signed-off-by: Gama <misept.dieseneuf@gmail.com>