Replace magic number (-1) with EOF constant. Jaavdoc.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/codec/trunk@1301755 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

src/main/java/org/apache/commons/codec/binary/BaseNCodec.java

@@ -32,6 +32,11 @@
  */
 public abstract class BaseNCodec implements BinaryEncoder, BinaryDecoder {
 
+    /**
+     * EOF
+     * 
+     * @since 1.7
+     */
     static final int EOF = -1;
 
     /**