generate Signature programmatically for example request

[kaizensoze]

http://docs.aws.amazon.com/AWSECommerceService/latest/DG/rest-signature.html

make sure it matches result in example:

j7bZM0LXZ9eXeZruTqWm2DIvDYVUU3wxPPpp%2BiXxzQc%3D