Also, make core_log() exactly equivalent to printf(), since the lack
of a drop-in universally usable printf() equivalent annoys me.
Note that this breaks compiled experiments. They'll be fixed in
the following commits.
This requires recompiling and flashing the runtime and the entire
storage area file system (ip address and idle kernel).
* with ppp the runtime is larger than 0x40000 now
* 0x60000 for the runtime should give enough space for a while,
even including a fatter scheduler or runtime components
in other languages
* for both pipistrello and kc705 this leaves the unused space
starting at a nice round number
* the relevant flashes nowadays are 0x1000000 large