Changing the constructors for service class
Fixed technical limitation around reading chunked protocol buffer stream

We have some technical limitations around the way google protocol buffers (proprietary Google source code) and the HTTP client(s) used by Restlet interact when the protocol buffer data is chunked over multiple objects. Based on inputs from developer, we need to chunk the protocol buffer into multiple objects on the server side or else we would run into memory issues.

So the current code is changed to read the protocol buffer into client memory till we can find better alternative.
The org.restlet.ext.net project provides low level HTTP connection using java.net.HttpURLConnection implementation.

This HTTP connector provides blocking I/O for the inputstream and hence can be used for protocol buffers; while for other streaming needs like file/document use the HTTP client connector.
Merge pull request #20 from anilallewar/2.1

Fixed technical limitation around reading chunked protocol buffer stream
added one more constructor to service class with functionhandler and challange scheme.
Merge pull request #19 from shantanud/2.1

Changing the constructors for service class to add username and password
Merge remote-tracking branch 'upstream/2.1' into 2.1