docs(readme.md): include references to S3 examples
docs(readme.md): include references to S3 examples

FineUploader/server-examples,FineUploader/server-examples,paul-herrmann/server-examples,FineUploader/server-examples,paul-herrmann/server-examples,FineUploader/server-examples,FineUploader/server-examples,paul-herrmann/server-examples,paul-herrmann/server-examples,paul-herrmann/server-examples,FineUploader/server-examples,paul-herrmann/server-examples,FineUploader/server-examples,FineUploader/server-examples,paul-herrmann/server-examples,paul-herrmann/server-examples