qml: initialize progress bar with 0
xypenplottercontroller: updated README.md

Extended information about shared memory variant.
xypenplottercontroller: update status correctly, implement homing
qml/xypenplottercontroller: fixed wrong image selection, status bar reset
xypenplottercontroller: shared memory communication support
xypenplottercontroller: use new memory layout/improve loading of firmware

The released eCos version uses a new memory layout, use mqxboot
accordingly.

Also read the result of mqxboot and wait for the eCos load pattern
to appear for a given time.
xypenplottercontroller: fixed mqxboot command

Since we run now from OCRAM we need to load the firmware also into
OCRAM. When loading the image, no special jump address is required
since the firmware is already running.
xypenplottercontroller: switch back to DRAM

Revert back to DRAM as default load location for the Plotter
firmware. The provided eCos kernel uses DRAM, hence we should use
DRAM by default too.