fix initialization order on Kobos

notably, this will set up input offsets for viewport stuff after the
input rotation has been set up.
move debug function handover, set viewport for Kobo Mini

in order to have debugging facilities in framebuffer:init(), we hand
over the debug function as soon as we can.

Also, set a viewport for Kobo Mini. Hopefully, it fits most people -
I can only test on my unit.
smaller viewport for Kobo H2O (bezel overlaps bottom)
update base: pull fixes