Update README.md
adding build badge to readme
Merge pull request #35 from vernak2539/add-build-badge

adding build badge to readme
removing unneeded !!, since err will either be null or an Error object
Merge pull request #36 from vernak2539/remove-double-bang

removing unneeded !!
Release 0.7.1
It's possible that the content-type header won't exist
Merge pull request #38 from tweettypography/master

It's possible that the content-type header won't exist
Release 0.7.2