Fixed ProtobufValue generation of data and strings
Added a protobuf header class

This class is probably going to store the protobuf header for every
packet, though I might just choose to pass on the session everytime
Removed wiretype dependency on encoding

Now it just autodetects it from te protobufvalue class
Added support for more packet IDs

and improved SKSession to store more needed data
Added support for repeated values in protobuf
Improved encryption handling