Fixes #9, stop interpreting 'id' field of documents as unique identifier.

Updated README.md
Code coverage support
Merge pull request #46 from revington/code-coverage

Code coverage support
Merge pull request #44 from juzerali/deploy-9

Fixes #9, stop interpreting 'id' field of documents as unique identifier...
Make this package easier to find on npmjs.org
Merge pull request #47 from elliotf/npm_keywords

Make this package easier to find on npmjs.org
fixes #50
fixes #50
fixed #49