A class for implementing a Signature Method

See section 9 ("Signing Requests") in the spec

Class Methods

The following methods can be invoked on instances of this class.

buildSignature(mixed pRequest, mixed pConsumer, \Framework\WebServices\OAuth\Token strToken)

Build up the signature
NOTE: The output of this function MUST NOT be urlencoded. the encoding is handled in OAuthRequest when the final request is serialized

checkSignature(mixed pRequest, mixed pConsumer, mixed strToken, string strSignature)

Verifies that a given signature is correct