Added Bottleneck and Rate Limiting section
Added oauth-signature-js to Authentication and OAuth

[oauth-signature-js](https://github.com/bettiolo/oauth-signature-js) - OAuth 1.0a signature generator

It should be added as there is no library listed that generates OAuth signatures. The one I developed is extensively tested and follows the spec.
Merge pull request #39 from bettiolo/patch-1

Add oauth-signature-js to Authentication and OAuth
Merge pull request #38 from SGrondin/master

Add Bottleneck and Rate Limiting section