Update README.md
Merge branch 'refactor-criteria-parse' into refactor-with-embed
check for undefined values
Merge pull request #157 from clarkorz/refactor-criteria-parse

Rewrite `lib/query.index.js` with more structural code
Merge remote-tracking branch 'upstream/master' into refactor-with-embed

Conflicts:
	lib/document.js
Merge branch 'refactor-with-embed'