Mask high bits in ChunkedInputStream.read

Previously read could erroneously return -1 end of stream when
returning ASCII 128.

src/main/java/org/gaul/s3proxy/ChunkedInputStream.java

@@ -56,7 +56,7 @@ final class ChunkedInputStream extends FilterInputStream {
             }
             readLine(in);
         }
-        return chunk[currentIndex++];
+        return chunk[currentIndex++] & 0xFF;
     }
 
     @Override