THRIFT-299. doc: binary type isn't documented nor demonstrated in the tutorial

The existence of the "binary" type is now documented in the relevant places. 

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@739702 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/doc/thrift.tex b/doc/thrift.tex
index 082be62..d20b737 100644
--- a/doc/thrift.tex
+++ b/doc/thrift.tex
@@ -163,6 +163,7 @@
 \item \texttt{i64} A 64-bit signed integer
 \item \texttt{double} A 64-bit floating point number
 \item \texttt{string} An encoding-agnostic text or binary string
+\item \texttt{binary} A byte array representation for blobs
 \end{itemize}
 
 Of particular note is the absence of unsigned integer types. Because these