Changing the data structure from string list + hash table to a list of KisSwatchGroup. This would make the logic in this class clearer and more efficient.

There is also minor interface change in KisPaletteModel, KisPaletteView and KisDlgPaletteEditor, as KoColorset now has a getGroups() method which is clearer than the original getGroupNames() method.

Also, fixed 2 issues related to file I/O of the palette.

One is that Krita crashes if a palette file it wants to load is corrupted. It is changed so that Krita aborts loading that file instead of crashing.

The other is that Krita would fail to store a kpl palette if multiple color profiles used in this palette are from one same profile file. This is fixed by saving one profile file only once.

I am trying to come up with a better inferface for KoColorset. I will provide unit tests once it is done. For now, I think testing renaming, reordering, adding and removing swatch groups manually in the GUI palette docker would be enough.

For the crashing issue when loading a corrupted file, try to let Krita load a corrupted palette file, like an empty file. Krita would crash before this fix. This should not happen after this fix.

For the saving multiple profile issue, before this fix, if in a palette there are 2 colors using different color profiles from one same profile file, Krita would fail to store that palette, causing the file its stores the palette to be empty. 2 colors that are close to each other on the advanced color picker are likely to cause this problem. This should not happen after this fix, either.