missing documentation

As noted by Daniel the Signature and Verify functions are not documented in the base specification. They should be documented with the same level of detail as the other functions.

C_MessageSignInit

C_SignMessage

C_SignMessageBegin

C_SignMessageNext

C_MessageSignFinal

C_MessageVerifyInit

C_VerifyMessage

C_VerifyMessageBegin

C_VerifyMessageNext

C_MessageVerifyFinal

Tim.