Distributed file cipher InputStream and OutputStream which provide 1:1 mapping of plain text data and cipher data.

To be easily seek and positioned read distributed file, the length of encrypted file should be the same as the length of plain file, and the positions have 1:1 mapping. So in this JIRA we defines distributed file cipher InputStream(FSDecryptorStream) and OutputStream(FSEncryptorStream). The distributed file cipher InputStream is seekable and positonedReadable. This JIRA is different from HADOOP-10151, the file may be read and written many times and on multiple nodes.