d2025.02

Rename core namespace to gfx.
Add PaletteV5 to accommodate namespace change.
Add TileSheetV5. TileSheetV5 retains the bpp field for the sake of CompactTileSheet, but always store it pixel as 8 bpp for itself.
Replace file picker combo boxes with a browse button and file picker, and support for dragging files from the project explorer.
Add ability to create directories.
Add ability to add files to specific directories.
Add ability to delete files from the project explorer.
Ctrl- keyboard shortcuts for jumping between tabs.
Fix Palette Editor to ignore keyboard input when popups are open.
Palette Editor move color mechanism now uses drag and drop.