the framebuffer "object" now has a "member" that exposes the blitbuffer
API for the framebuffer pixmap. This allows to reuse blitting & Co for
blitbuffer-to-blitbuffer operations
this allows to render glyphs and also brings a simple
engine for rendering UTF-8 strings onto the framebuffer.
blitting to uneven offset is implemented here, too, but
needs more work and is still buggy.
In the end, this will allow for a simple GUI.
The sources can now conditionally compile emulation code
for the e-ink framebuffer and input events.
It uses SDL for doing that, so you need this installed
if you want to use emulation (you do not need it if you're
only compiling for the e-ink device).
This allows for rapid testing of new code.
