Polishing fixes

Polishing fixes

 - Replace Handshake::details pointer with an always-available object
 - Replace Security::ProtocolVersion and its "int" representation in TlsDetails
   and NegotiationHistory classes with the existing Anyp::ProtocolVersion
 - Fix TlsDetails::compressMethod. The clients may send a compression methods
   list with a NULL compression method.
   Rename to TlsDetails::compressionSupported.
 - Other minor fixes.