block: move rc5/6 ciphers from stream directory

CMakeLists.txt

@@ -40,15 +40,15 @@ list (APPEND sources
     stream/rabbit.hpp
     stream/rc4.cpp
     stream/rc4.hpp
-    stream/rc5.cpp
-    stream/rc5.hpp
-    stream/rc6.cpp
-    stream/rc6.hpp
     stream/salsa.cpp
     stream/salsa.hpp
 
-    block/speck.hpp
+    block/rc5.cpp
+    block/rc5.hpp
+    block/rc6.cpp
+    block/rc6.hpp
     block/speck.cpp
+    block/speck.hpp
     block/tea.cpp
     block/tea.hpp
     block/xtea.cpp