MD5Builder tests have been randomly, non-repeatably failing due to a problem
with the returned value of MD5Builder.
Valgrind detected a strncpy with an overlapping memory range, which is
an undefined operation. Fix it with a memmove instead, and get rid
of a couple #define redefinitions which were causing compile warnings
on the host side as well.
This includes empty stubs for most core Arduino functions.
Need to actually implement all those digital reads writes whatever.
Need to prebuild toolchains (xtensa-elf-lx106) for 3 platforms and put them on some download server.
Need to do the same with esptool.
Need to fix 0x40000 binary generation and add correct upload commands.
Maybe even implement uploads over WiFi.
