Update readme.md

Fixed grammar and punctuation throughout.  Revises phrasing in a couple places as well.
Update readme.md

added comma
Update readme.md
Update readme.md

removed unnecessary 'that'
Update readme.md

Added 2 commas and 'an' to line 88 & 89
Update readme.md

Added 'a' to line 6.
Merge pull request #770 from iepathos/master

Corrected all of the readme