Merge pull request #76 from markstos/callback-with-correct-error-in-authenticate

BugFix: When the JSON parsing of the auth response fails, the callback was reporting success.
Merge pull request #75 from markstos/improve-data-name

Refactor: Improve variable names by avoiding generic 'data' variable name.
Merge pull request #78 from markstos/fix-passing-arguments-to-request

Fix authentication.
Remove the dead _requestHandler function.

This was first spotted by @nixta. This is just a smaller, simpler pull
request to review and merge.

Also, the stringify variable was only used in one place so I inlined the
single use of it to simplify things a bit.
Fix #62 again. Use SSL for geocoding calls. It's better for security and privacy, and

also fixes things organizations set to SSL only.
Upgrade authentication docs to make them more complete, accessible.

* document how it's intended to be used-- as a mix-in
* documennt side-effects-- it sets some properties on the calling
* document what args are passed to the callback called.
* Link to related REST API documentation
Merge branch 'improve-authentication-docs' into ra-fixes-new
Merge branch 'remove-dead-code-in-feature-service' into ra-fixes-new