Bug #468, http://bugs.skysql.com/show_bug.cgi?id=468, Query classifier accessed freed thread context. If parsing fails thd doesn't need to be freed because it holds correct information about command type.

session.c:session_setup_filters : fixed memory leak
hintparser.c: added token_free for HINT_TOKENs and fixed a few memory leaks.
mysql_client_server_protocol.h: added mysql_protocol_done which frees memory blocks pointed to by protocol members. Those can't be freed in dcb.c because dcb.c doesn't know about protocol's members.
mysql_backend.c:gw_backend_close: fixed memory leak
mysql_client.c: gw_client_close: fixed memory leak
mysql_common.c: added implementation of mysql_protocol_done
        :protocol_archive_srv_command: tried to fix memory leak. Some memory is still leaking according to valgrind. Removed use of uninitialized local variable len.
readwritesplit.c: Fix to bug #469, http://bugs.skysql.com/show_bug.cgi?id=469,  rwsplit counts every connection twice in master - counnection counts leak
	execute_sescmd_in_backend: fixed a memory leak - visible only in DEBUG=Y build.
readwritesplit/test/makefile: added target for hints tests

utils/skygw_debug.h

@@ -133,7 +133,8 @@ typedef enum skygw_chk_t {
                        ((t) == QUERY_TYPE_SESSION_WRITE ? "QUERY_TYPE_SESSION_WRITE" : \
                         ((t) == QUERY_TYPE_UNKNOWN ? "QUERY_TYPE_UNKNOWN" : \
                          ((t) == QUERY_TYPE_LOCAL_READ ? "QUERY_TYPE_LOCAL_READ" : \
-                          "Unknown query type")))))
+                          ((t) == QUERY_TYPE_EXEC_STMT ? "QUERY_TYPE_EXEC_STMT" : \
+                          "Unknown query type"))))))
 
 #define STRLOGID(i) ((i) == LOGFILE_TRACE ? "LOGFILE_TRACE" :           \
                 ((i) == LOGFILE_MESSAGE ? "LOGFILE_MESSAGE" :           \