Update newrelic.ini config to use heroku config vars

Using https://devcenter.heroku.com/articles/newrelic#node-js-agent-on-heroku as a guide, this seems like the thing to do.

Additional new relic should be put in code and should use the extra.heroku.php-includes option in composer.json
Package sundown extension
Add application/x-javascript to GZIP types. Fixes #77
Add Changelog for v0.3.4
Merge branch 'development'
Add note about sundown extension
Update nginx config to pass parameters to Slim
Merge pull request #83 from ciaranmaher/slim-config

Update nginx config to pass parameters to Slim
Update Newrelic to 4.4.5.35
Merge branch 'master' into development
Merge branch 'master' of github.com:Azer-/heroku-buildpack-php into Azer--master

Conflicts:
	bin/compile
Merge branch 'Azer--master' into development
Enable Freetype support in GD
Use 5.5.9 as default
Listen for app_dev.php and config.php too for Symfony apps, let Symfony
handle the access control to these files. Fixes #87
Merge branch 'master' into development
Zend Framework support
Fixed nginx conf
Add DOCUMENT_ROOT check
Merge pull request #93 from GlobalLynx/master

Zend Framework 2 support