Add command to display a bitmap on OLED screen

[jose1711]

duckyPad's display is both small and monochrome so I think it would make sense to have a command to display an arbitrary bitmap (e. g. a logo or a text in custom font and/or additional graphical elements). The bitmap would be stored on SD card (e. g. in img/foo.bmp) and the command syntax could go

OLED_BLIT foo

[jose1711]

Experimental implementation is at jose1711@0fd8e1c

[jupiterbjy]

Totally love this idea - could be used as a startup splash screen sort of.

Feels like even a command to set a single pixel instead of character - people could do so many things with it. With all that features in duckyscript3 one could draw animation out of it, who knows!