Added aws sdk for php
Parameterized Pigallery.php to hold the aws creds

In order to introduce S3 function the Picgallery.php class
will require a phing step to populate the AWS credentials. These
will be loaded as the defined constants AWS_KEY and AWS_SECRET.
Moved aws credentials to config.php.in
Updated .gitignore because of config.php.in intro
build.xml config file uses config.php.in
Added S3 file store source
Created factory method for S3 file store
Merge branch 'master' of https://github.com/ahaley/Picgallery