Work for making the buildpack also a drop in replacement for the official PHP buildpack
Fix path to default framework
Don't run composer when no composer.json
Mirror zlib tarball in S3 and use mirrored tarball for packaging

When a new Zlib release comes out, the previous release is not available
anymore at zlib.net/zlib-{version}.tar.gz. This breaks the packaging
process.
Add CONTRIBUTING
Update changelog
Add note about usage
Remove not implemented status for 'compile' setting
Update stack
Add note about detection of classic mode apps
Some cleanup
Add APCu
Fix path to pecl executable, add apcu.so in default php.ini
Add link to ZendOpcache pecl page
Merge branch 'feature/apcu' into development
Enable postgres, fix framework detection
Saner framework handling
Better log messages
Site configs are now included in server scope
Include .nginx_config from document root when exists