graphics/xaos: update to 4.2

From ChangeLog: https://github.com/xaos-project/XaoS/releases/tag/release-4.2

• Palette editor, save/load palettes, storing user palettes in the .xpf file.
• The option 'User formulas' maintains a history of recently used formulas.
• Fractal info in the Help menu.
• Batch rendering.
• Enabled panning in rotate mode.
• Unified Open and Open Image option. Save Image option moved to Save as.

Reported by: portscout