This commit adds initial files for the Sphinx documentation system and
expanded checkcode.sh to include `doc8` as documentation checker. Also
added this checker to the dependencies for travis CI.
Signed-off-by: Claudius Heine <ch@denx.de>
Build the docker image in Travis. Push the result as latest version if
run from the master or next branch. Only push tagged commits from the
master branch as releases.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>