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.
