There are a few places in the system where this could be useful,
such as PixelPaint and the MandelBrot demo. It seems general enough
that it is probably useful to have it as a system-wide cursor rather
than loading it manually each time.
This can be used immediately in PixelPaint (separate commit), but
I am adding this as a system-wide cursor since it may also be useful
for other applications that want to use it.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
