some work done in Chapter4
Fix some column issues
Up until p134 mid
Merge branch 'master' into Chapter4

* master:
  A bit of work on chapter 9
  Correcting one more error
  Chapter one corrected
  I'm working on typing up Chapter 4.
  updated readme
  Applied corrections to chapter 7
Merge branch 'master' into Chapter4

* master:
  Updated PDFs
Some more work on chapter4
Up until 4.2
Merge branch 'master' into Chapter4

* master:
  Finished Part 12 (chap 9), added rot operator
Merge pull request #19 from bimmlerd/Chapter4

Beginning of Chapter4