Tile selector improvements

[neomoth]

Hey, I have a few ideas that might make the editor a little bit more convenient to use, mainly revolving around the tile selection.

• Make the selector window resizable, as in being able to drag the side to make it wider. Personally i think having the window stuck in a small and slim vertical form factor is a bit annoying to deal with, especially so if zoomed in
• Make selecting a new palette reset the camera in the tile selector window to the top left tile, selecting a new palette usually causes me to get lost trying to find the tiles again which is annoying