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.
Now there is a generic resource that can generate and parse
application/json as well as text/plain. It can be re-used, only the
from_string and to_string routines have to be written and the resource
properly set up. A new resource format is specified, see
GENERIC_RESOURCE in, e.g., examples/osd/pwm-example. This is now used in
all my examples, namely pwm-example, arduino-sketch, wallclock-time.
There was an off by one error for the month in time formatting (in
gmtime and localtime). And the leap-year computation was broken. Both
fixed now, so we get a correct date. For localtime we are still 2 hours
off because daylight saving isn't implemented yet.
Also renamed gmtime to utc.
