Make use of button well colour option for Raspberry theme
The Raspberry Pi theme is derived, with permission, from the Steel theme designed by Chris Wraight.
Wimp 5.81 added WimpVisualFlags which allow the button colours to be customised per theme, but since their introduction Chris has been uncontactable to get his input on which aspects of the Steel theme he wanted to change to make use of these new features. Looking at the Steel theme it may have be intended to change the window/menu tiles to be more blue to appear metallic, at which point changing the button faces would be desirable.
For now, the button faces and borders in the Raspberry theme have a similar tone to tile_1, but the yellow well around a default action button jars with the focus window title bar yellow. Change the button well colour to match that more orangey-yellow, leave everything else the same.
Add a new vcddisc icon to the sprite pool for CDFSFiler.