Fix example so that it compiles with Visual Studio 2013.

Author: chriskohlhoff

asio/src/examples/cpp11/go/echo_server.cpp

@@ -35,7 +35,7 @@ class session : public std::enable_shared_from_this<session>
     auto self(shared_from_this());
 
     std::size_t n = 0;
-    char data[128] = "";
+    std::array<char, 128> data;
 
     asio::go(strand_,
         [this, self, n, data](asio::stackless_context ctx) mutable