WL#5625: Deprecate mysqlbinlog options --base64-output=always and --base64-output

NOTE: 2010-10-20:  Feedback was solicited from stakeholders,
but no decision has been made.
NOTE: 2010-10-27: ServerPT approved the proposal to deprecate the
mysqlbinlog options in Celosia and generate errors for them in
Dahlia.


Beginning with the work done for WL#344 (Time-delayed Replication),
the server can parse BINLOG statements only for row events and format 
description events. For other BINLOG statements (such as
those for SQL statements, as generated by the mysqlbinlog option
--base-output=always (or --base64-output without any option value),
the server generates errors.

This should not be a significant problem because --base64-output=always
is supposed to be used only for debugging, not for production
environments. But we to have mysqlbinlog not generate BINLOG
statements that the server cannot parse.

The proposal is: 
 
* Add deprecation warnings to mysqlbinlog for --base64-output=always
and --base64-output in MySQL 5.5 (Celosia).

* In the next series (Dahlia), have mysqlbinlog generate an error if
--base64-output=always or --base64-output are used.