Adjust bootstrap_osx.sh for new shell-session type

O'Reilly has changed "shell" types to "shell-session," thus we need a
new custom type in the bootstrap script.
ce prep and adding figures to book repo
taking off image width boundaries
Update CONTRIBUTING.md
Update CONTRIBUTING.md
Remove chapters list from CONTRIBUTING
Update README.md
Add a bit more description to README
Update README.md
Organize frontmatter/ a little better

- Move non-conventions into frontmatter.asciidoc
- Create separate acknowledgements.asciidoc file
Change cookbook URL back to italics as per conventions
Merge branch 'master' into atlas-master
Flow frontmatter so it is easier to read in editors
Add acknowledgements