Support for non seekable streams as NetworkStream.

[pack7df]

SignatureReader for instance, it makes use of Length and Position of stream. If the stream is a NetworkStream it would throw an exception. What i did to support it, is to send an empty end chunk in the client and create a copy of the SignatureReader class but removing that lines using position and length, and using the last chunk as the end of stream. BinaryDeltaReader does something like this also.