fix printing

include/sp/protocol/MessagePrinter.h

@@ -4,6 +4,8 @@
 #include <sp/common/Reflection.h>
 #include <sp/protocol/message/MessagePrinterImpl.h>
 
+namespace sp {
+
 /**
  * \brief Prints a message in a human readable string
  */
@@ -17,3 +19,5 @@ std::ostream& operator<<(std::ostream& a_Stream, const sp::MessageBase<TBase, TO
 		<< "]";
 	return a_Stream;
 }
+
+} // namespace sp