* Update Arranger Clip Rendering

Clips are now rendered with 3 component:

- Brightest colour: clip head
- Less bright colour: clip loop point
- Dim colour: clip tail

* Change doubles to floats

* Render tail for empty clip instance

New white clip instances are created without a clip assigned to it. Previously tails for these instances were not rendered. Now we render a tail so that you can know where to press to enter the clip.