Merge pull request #15 from zaxtax/master

Fixed some typos
cleaning up
CH2: misc fixes
CH1: various fixes
Merge pull request #16 from y-p/CH1

CH1: misc fixes
Merge pull request #17 from y-p/CH2

CH2: misc fixes
premerge with y-p
premerge chp1
merged y_p changes + updates plots.
redid intro
readme additions
readme additions
edits to mcmc in chapter1
edits to mcmc in chapter1
edits to mcmc in chapter1
edits to mcmc in chapter1
edits to mcmc in chapter1
Spelling and grammar edits.
Merge pull request #20 from etano/master

Just spelling and grammar from Chapter 1
readme: adding Ethan Brown