Problem: mysqlbinlog does not free memory if an error happens.
Fix: binlog-processing functions do not call exit() anymore. Instead, they
print an error and return an error code. Error codes are propagated all
the way back to main, and all allocated memory is freed on the way.


client/mysqlbinlog.cc:
  - New error handling policy: functions processing binlogs don't just
    exit() anymore. Instead, they print a message and return an error
    status.
  - New policy for the global `mysql' and `glob_description_event': these
    are not passed as parameters anymore. The global pointer is used
    instead.
  - More error situations are detected and reported.
  - Better error messages: the program never terminates with exit status 1
    without explanation any more. Fixed spelling errors. Use consistent
    format of messages (a single line beginning with "ERROR: " or
    "WARNING: " and ending with "." is printed to stderr.)
  - New memory handling: memory is always freed on program termination.
  - Better comments: more functions are explained, doxygen is used, and
    more precise formulations in some existing comments.
mysql-test/suite/binlog/r/binlog_base64_flag.result:
  Result file updated since output format of mysqlbinlog changed while the
  test was disabled.
mysql-test/suite/binlog/t/binlog_killed.test:
  Mysqlbinlog now works as described when the binlog is open. Hence, the
  --force-if-open flag must be passed
mysql-test/suite/binlog/t/binlog_killed_simulate.test:
  Mysqlbinlog now works as described when the binlog is open. Hence, the
  --force-if-open flag must be passed
mysql-test/suite/binlog/t/disabled.def:
  Now that mysqlbinlog cleans up after itself on abnormal termination, we
  can enable this test again.