Added section for filecmp.

Doc/lib/lib.tex

@@ -133,6 +133,7 @@ add new extensions to Python and how to embed it in other applications.
 \input{libstat}
 \input{libstatcache}
 \input{libstatvfs}
+\input{libfilecmp}
 %\input{libcmp}
 %\input{libcmpcache}
 \input{libtime}