Pico Scroll and Pico Unicorn were allocating static buffers for gamma and font data respectively.
Make Pico Scroll's `__bitmap` static.
Move Pico Unicorn's three GAMMA tables to one 14-bit table in "pimoroni_common.hpp". Rename "GAMMA" to "GAMMA_8BIT".
Moves the 256 entry GAMMA table into pimoroni_common.
Should probably be added into a library so MicroPython is built with only one instance of the table.
"RGBLED" PWMs 3 pins as a single RGB LED and exposes methods to set the colour via HSV/RGB.
"Button" handles tracking the state and changed state of a single GPIO button, in addition to supporting auto-repeat for held-down buttons.
Phil Howard