Implement a mechanism that allows us to alter colors so that they
mimic those a colorblind person would see. From the color we can then
alter the colors for the whole preview so we can simulate everything
in the theme including icons/decorations.
This filter is also available as a Filter in LibGfx so it can be
reused in multiple other places.
The color simulation algorithm is based on this one
https://github.com/MaPePeR/jsColorblindSimulator publicly available.
Prior to this change, the 'Save' action was saving a file to the startup
path (or just showed a File Picker dialog) if a file has been opened
by the Open action or by drag-n-dropping a file to the program.
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 *
