Merge pull request #29 from jwsy/master

ch04 minor update for improved directory structure - Thanks @jwsy
Fixes #10-12, #17, #19-23. Thanks so much to @pfaffman for the incredibly detailed feedback!
Fixes #13. Thanks for the idea pfaffman!
updating chapter1 with conventions for tooling (moving markdown as needed)
Reworking images in FB notebook (fixes #24) and reworking example numbers as part of retooling
As of this commit, I have fixed #6 #24 #26 #27
Fixes #14 - updated header to follow other existing conventions with number of chapter