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".
Move scroll_text into the C++ library and make it support std::string.
Move show_bitmap_1d to set_bitmap_1d in the C++ library. Use it as the basis for show_text and scroll_text.
Change show_text to set_text since it does not implicitly show the result.
Add a new pico-scroll demo to show off the scrolling text functionality.
Phil Howard
ZodiusInfuser
Jonathan Williamson