Update Chapter9.ipynb

oauth_login needs to return a twitter_api obj
Merge pull request #45 from jwsy/patch-4

Update Chapter9.ipynb (oauth_login needs to return a twitter_api obj). Thanks @jwsy!
Fixes #47
Fixes #46
Minor formatting/language updates

Also expanded an example in Chapter9 to be more illustrative
Renaming notebooks to mirror the book's TOC.
Renaming resources folder to be consistent with notebook name
Fixing links in README to read-only ipynb viewer

Also added missing file (Chapter 9) from last commit
Formatting updates to README
Formatting updates to README
Formatting updates to README
Minor updates to README
Fixing typo in filename
Updated preface notebook
Fixed header in Appendix C
Fixed links that didn't hyperlink in read-only viewer
Re-organizing some of the README and appendix content
Initial draft of Appendix A - VM Experience

Completed initial draft of Appendix A on getting the virtual machine and
developer tools installed. Fixes #41, fixes #42, and fixes #43. Thanks
so much to @magyar666, @carltongibson, and @welenofsky for the
suggestions and help with this.
Update chef recipe
Merge remote-tracking branch 'upstream/master'