Implement Zoom tool in Sprite Editor

[jjant]

Description

Pico8 features this zoom tool: which lets you edit a bigger portion of the sprite sheet at once.

It allows selecting between 4 zoom levels:

• 1X (1x1 sprites)
• 2X (2x2 sprites)
• 4X (4x4 sprites)
• 8X (8x8 sprites)

Setting flags while selecting many sprites (with the >1X zoom levels) sets the flag for all sprites in the selection (general care is needed around flags in these cases).