Squashed 'json/' changes from 3cef243..9208016

9208016 Merge pull request #67 from iainbeeston/defaults
f57888c Added tests around the default property
db28fee Merge pull request #63 from iainbeeston/patch-1
609944b Added the json-schema ruby gem to the list of libraries using the test suite

git-subtree-dir: json
git-subtree-split: 9208016d04c1b6774d5a17e8b037161873414edb
Merge commit '45cf1fb8a6a0b7ea1ab8de8ea9fc7addb0ffd149'

* commit '45cf1fb8a6a0b7ea1ab8de8ea9fc7addb0ffd149':
  Squashed 'json/' changes from 3cef243..9208016
Slightly clarify the wording, which means to refer to calling this method directly.