W3C Fix for FacebookRedirectLoginHelper.php

Change & to &amp; to be compilant with W3C checks.
Adding developer site doc content, needs lots of updates.
Add FacebookApp entity
Namespace tests and add licence header
Merge pull request #163 from yguedidi/namespace-tests

Namespace tests
Merge pull request #162 from yguedidi/facebook-app-entity

Add FacebookApp entity
Rename FacebookRequestException to FacebookResponseException
Update FacebookApp tests and add copyright header
Fix Mockery
Merge pull request #165 from yguedidi/facebook-app-tests

Update FacebookApp tests and add copyright header
Merge pull request #164 from yguedidi/facebook-response-exception

Rename FacebookRequestException to FacebookResponseException
Merge pull request #166 from yguedidi/fix-mockery

Fix Mockery
Merge pull request #156 from micressor/patch-1

W3C Fix for FacebookRedirectLoginHelper.php