Also get rid of genbackupisr hack: We can achieve the same thing with
avr-objcopy which doesn't need additional software.
We use the new bootloader setting for irq-save area of 0x800.
Introduce new testing-app example.
Add a new coap error code for blockwise transfer.
Add include-file for bootloader callbacks (jumptable).
Note that only the bootloader for osd-merkur-256 will support
OTA-update, the -128 simply has not enough flash memory, so only
in the -256 we have the bootloader functions in the jump-table
of the bootloader and in the bootloader-if.h include-file.
Rename guhRF platform to osd-merkur-256, previous osd-merkur platform is
now osd-merkur-128. Also check that everything is consistent.
Add both platforms to the regression tests.
Move redundant files in platform dev directory of both platforms to
cpu/avr/dev. Note that this probably needs some rework. Already
discovered some inconsistency in io definitions of both devices in the
avr/io.h includes. Added a workaround in the obvious cases.
The platform makefiles now set correct parameters for bootloader and for
reading mac-address from flash memory.
Factor the flash programming into cpu/avr and platform/osd-merkur* and
rework *all* osd example makefiles to use the new settings. Also update
all the flash.sh and run.sh to use the new settings.
The suli ledstrip modules (and osd example) have also been removed.
