This patch makes use of the recently added support for const RPC
functions by turning 'Framebuffer::Session::mode()' and
'Input::Session::is_pending()' into const functions.
The new d3m component is the designated device-driver manager for the
upcoming live CD. It addresses the auto probing of USB storage and ATAPI
boot devices (issue #94) and the aggregation of user input coming from
USB HID and PS/2.