Fix dll-interface annotations on parser/request/response bases

Author: sentientsergio

include/boost/http_proto/parser.hpp

@@ -98,7 +98,7 @@ class BOOST_HTTP_PROTO_DECL parser
             @ref response_parser::get,
             @ref request_parser::get.
     */
-    BOOST_HTTP_PROTO_DECL
+
     bool
     got_header() const noexcept;
 

include/boost/http_proto/request_base.hpp

@@ -285,7 +285,6 @@ class BOOST_HTTP_PROTO_DECL request_base
         @param b If `true` sets `Expect: 100-continue`
         header otherwise erase it.
     */
-    BOOST_HTTP_PROTO_DECL
     void
     set_expect_100_continue(bool b);
 

include/boost/http_proto/response_base.hpp

@@ -141,7 +141,6 @@ class BOOST_HTTP_PROTO_DECL response_base
 
         @param v The version to set.
     */
-    BOOST_HTTP_PROTO_DECL
     void
     set_version(
         http_proto::version v);