Developer's note:

This version adds support for a "drop" event to enable drag-and-drop functionality. The ScrollingPanel has been refactored to fix the bugs spotted by DoZ. It includes a new ColourPicker gadget supplied by Mark Adamson that allows a colour to be chosen by manipulating RGB sliders. It is built with devKitARM r30 and includes the usual set of bugfixes.

Fixes:
- Removed Woopsi::startup() call from template.
- Fixed bug in Gadget::checkCollision(x,y,width,height).
- Renamed CalendarDayButton to StickyButton.
- WoopsiKey inherits from StickyButton instead of Button.
- ScrollableBase no longer contains implemented methods or data; all moved to ScrollingPanel.
- Child gadgets of ScrollingPanel no longer get drawn to wrong screen if scrolled out of top of panel; Gadget::getPhysicalScreenNumber() is more intelligent.
- Graphics::scroll() returns correctly-sized rects in revealed rects array.
- Replaced WindowBorderBottom, WindowBorderTop and WindowBorderSide classes with more elaborate drawing code in AmigaWindow class.
- Replaced ScreenTitle class with more elaborate drawing code in AmigaScreen class.
- Made ScrollableBase a base class of ScrollingTextBox; implemented all pure virtual functions.
- ScrollingListBox raises value changed, action, click, release, release outside and double-click events correctly.
- RadioButtonGroup raises value click, release, release outside and double-click events correctly.

New Features:
- Added x and y parameters to Gadget::stopDragging().
- Added drop event (drag-and-drop).
- Added Gadget::isBeingDragged().
- Added PipeDream demo.
- Built with devkitARM r30.
- Added ScrollbarPanel gadget.
- Added ColourPicker gadget (contributed by Mark Adamson).
- Added ColourPicker test.
- Added ScrollingPanel::isContentScrolled() and setContentScrolled() to allow DMA copying of panel contents to be disabled if not needed.