If one of the default pins was already in use it would crash.
The internal API has been refined to allow us to get the value
without causing an init of the singleton.
Fixes#1753
* Fix Hallowing.
* Fix builds without displayio.
* Fix y bounds that appears as untrollable row of pixels.
* Add scrolling to TileGrid.
* Remove Sprite to save space. TileGrid is a drop in replacement.
It's designed to minimize RAM footprint by using Sprites to
represent objects on the screen. The object model also facilitates
partial screen updating which reduces the bandwidth needed to display.
This is all handled in C. Python simply manipulates the objects with
the ability to synchronize to frame timing.
Scott Shawcroft
Melissa LeBlanc-Williams
Dan Halbert