The calculation did not correctly calculate the offset in rotated
modes when the rotation was 90 or 270 degrees. Under these circumstances,
getWidth() and getHeight() did return rotated values for the framebuffer,
while Device.viewport did return not rotated values.
WIP, untested, can probably simplified some more.
Good news is, it should be smarter, and thus provide a smoother user
experience :).
Relies on the relevant changes in base.
This is a major overhaul of the hardware abstraction layer.
A few notes:
General platform distinction happens in
frontend/device.lua
which will delegate everything else to
frontend/device/<platform_name>/device.lua
which should extend
frontend/device/generic/device.lua
Screen handling is implemented in
frontend/device/screen.lua
which includes the *functionality* to support device specifics.
Actually setting up the device specific functionality, however,
is done in the device specific setup code in the relevant
device.lua file.
The same goes for input handling.
