Correct package.json license syntax

There are two formats for package.json license statements:

 "license" : "BSD-3-Clause"

AND

"licenses" : [
  { "type" : "MyLicense"
  , "url" : "http://github.com/owner/project/path/to/license"
  }
]
Merge pull request #56 from prescod/patch-1

Correct package.json license syntax