Implement the KW and KWP algorithm

1. Add kw to the Makefiles
2. Implement the algorithms as defined in SP800-38F, and RFC 3394.
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 4aba062..70fff52 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -40,6 +40,7 @@
     md5.c
     md_wrap.c
     memory_buffer_alloc.c
+    nist_kw.c
     oid.c
     padlock.c
     pem.c