hadrian bootstrap tweaks

The last MR to the hadrian/bootstrap directory resulted in the README.md file commands working.

These patches add -w to all README.md file bootstrap.py commands and fix in bootstrap.py the shell messages.

bootstrap.py

Still, it might be pointed out that {args.deps} should be copied to plan-bootstrap.json.

Download the files listed in {args.output} and save them to a tarball ($TARBALL), along with {args.deps}
The contents of $TARBALL should look like:

./
./plan-bootstrap.json
./{tarfmt.join(path for path in plan)}

If the directory name for the downloaded files is sources-tarball then an example command to generate the $TARBALL would be as follows.

cd sources-tarball && tar -zcvf ../sources-tarball.tar.gz . && cd ..