Use the most recent example keys from AWS docs
Initial implementation of querystring signatures

This includes a lot of copy-pasta from AWSRaw::S3::Signer, which
needs to be factored out
Make QueryStringSigner a subclass of Signer
Expand QueryStringSigner documentation

Explains the reasons why one would want to use this class
instead of S3::Signer.
Simplify the QueryStringSigner API

Instead of accepting a bucket/key pair and optional headers,
we should be opinionated. This class's primary use case is for
signing a known URL, so let's optimise for that. We can assume
that the caller's user-agent won't be sending a bunch of custom
headers, so we don't accept that hash any more either.
Generate a fully signed URL
Merge pull request #1 from dgoodlad/query-string-signatures

Generate query string signatures
Add some simple docs and background in a README
Add David Goodlad as an author
Version bump to 0.1.0, with new functionality

* Added S3 query-string url signing
Fix up examples in the README
Merge pull request #2 from dgoodlad/release-0.1.0

Release 0.1.0
Use the MIT license, attributed to Envato, PY & DG
Release version 0.1.1

* Officially license under MIT
Merge pull request #4 from dgoodlad/license

License under MIT
Support non standard regions.
Improve the formatting of the request spec.
Don't use region host if the region us us-east-1.
Add MD5Digester class
Add support for passing in a File into content