Implement Client#copyTo and Client#copyFileTo for copying files between buckets.
Bonus fix indentations
Make `getCopyHeaders` private.
Document new `copyTo`/`copyFileTo`.
Release 0.5.0
Oh no, I forgot to press Ctrl+S before committing this!
add DEBUG support
fix Client#signedUrl() query-string param support

otherwise response-content-disposition etc break the signature
Release 0.5.2
Don't set token header when token is `undefined`.

Check the type of the `token` property since using `in` will return `true` when the property is set but `undefined`.
Document `http`/`https` URL-creation methods.

Closes #142.
Fix `signedUrl` tests.

Broken by 4825a117a4c080847fd6856704af65618cd3999f.
Release 0.5.3
fix Client#signedUrl() resource with url encoded queries
Add support for arbitrary verbs to presigned URLs.
Fix tests after e5ffa8d2e873cd9c942c3551547aa3c8549a499f.
Release 0.5.4
Add STS support for signed URLs.
Support Unicode in signedUrl params. Fixes #149.
Release 0.5.5