Fix windows linker errors (#120)

include/cppkafka/utils/compacted_topic_processor.h

@@ -37,6 +37,7 @@
 #include <boost/optional.hpp>
 #include "../buffer.h"
 #include "../consumer.h"
+#include "../macros.h"
 
 namespace cppkafka {
 /**
@@ -110,7 +111,7 @@ private:
 };
 
 template <typename Key, typename Value>
-class CompactedTopicProcessor {
+class CPPKAFKA_API CompactedTopicProcessor {
 public:
     /**
      * The type of events generated by this processor