Check that building the eboot.c block generates the same binary as
the verison checked into the repo. Catches the case where a library
or eboot.c file is changed, but an updated eboot.elf isn't included
in a PR.
Can't do simple binary diff of the ELFs because paths and compile
times will change, so dump the two sections we care about.
Convert the continuous integration process to use GitHub's internal
CI cloud. Allows us to run up to 20 jobs in parallel, speeding up
CI immensely. Keep a short Travis-CI run, too, just for sanity and backup.
Uses new keys and secret when publishing a release to
esp8266.github.io.
