Request for comments: Customizable image based watchface

Edit: Spoken too soon... Had inadvertendly compared execution from RAM via IDE with running from flash... Still, a few ms can be gained.

Moving up the scopes when using global variables seems extremely expensive. I have changed to giving the resource definition as function parameter instead of using the globally defined variable and the digitalretro watchface went from 1360ms to about 970ms, so about 30% faster 😱
The performance page in the documentation says that globals are slower to find, but finding out by how much suprised me.