* Move PiTrex display code out of dummy driver and into an
  independent graphics driver.

* Fix segmentation fault on shut-down

* Find better default dettings for vectrex mouse input driver

* Automatic display scaling in display driver

* Move uninterruptable vector drawing code to the GPU

* Support key name strings instead of numbers in key assignments
  for vectrex keyboard input driver (probably too much work to do
  that from the server side though)

* Support curved shapes (circles etc.) directly (though they're
  not really used much, so probably not)

* Tidy up fixes to modern ARM/Linux/GCC compatibility in general X
  code