THRIFT-4571: Updated ZeroMQ examples to ZeroMQ version >= 3.0. (#1556)

* New style for Python is default now.
* Symbols were replaced in newer versions of ZeroMQ (>=3.0).
* Use Thrift's abstraction for `shared_ptr` instead of Boost.
* Symbols were replaced in Python as well.
diff --git a/contrib/zeromq/TZmqServer.cpp b/contrib/zeromq/TZmqServer.cpp
index f031458..4df6c92 100644
--- a/contrib/zeromq/TZmqServer.cpp
+++ b/contrib/zeromq/TZmqServer.cpp
@@ -21,7 +21,7 @@
 #include <thrift/transport/TBufferTransports.h>
 #include <boost/scoped_ptr.hpp>
 
-using boost::shared_ptr;
+using apache::thrift::stdcxx::shared_ptr;
 using apache::thrift::transport::TMemoryBuffer;
 using apache::thrift::protocol::TProtocol;