added lab8 with outline and plotting reference
added preprocessing notes and a starter for the income challenge
cleaning up the preprocessing notes
added notes about dict vectorizer
a more cleanup
fix up readme
Merge pull request #22 from ga-students/lab_dev

Lab 8
before class 8
class 8
Merge branch 'master' of https://github.com/ga-students/DAT_SF_11
after class 8