features refining
Merge branch 'master' of https://github.com/krasnobaev/GetData_PA2

* 'master' of https://github.com/krasnobaev/GetData_PA2:
  Update README.md
  Update README.md
  Update README.md
  Update CodeBook.md
  Update CodeBook.md
  Update CodeBook.md
  Update CodeBook.md