The way is now open to schg and sappnd key files and directories in
our tree. There are recommendations in bin/15229.
PR: bin/15229
Reviewed by: imp, brian
2. Clean up code so it compiles -Wall (except for sccsid's and copyright).
This included fixing several printf formats that where not correct,
and changing the data types of a few things.
3. Implement new option -i that produces indented mtree output files.
4. Implement new option -n that turns off directory comments.
5. Only emit /set records if something has changed since the last one.
