Documented some binlog events using doxygen. More will be done later.
Also fixed typos in other comments and added remarks about dubious code.
Only comments are affected, there is no change to the actual code.


sql/log_event.cc:
  Fixed typos in some comments.
  Added remarks (as comments) about questionable code.
sql/log_event.h:
  Documented the binary format of following binlog events:
  Log_event
  Query_log_event
  Muted_query_log_event
  Slave_log_event (partial)
  Load_log_event
  Intvar_log_event
  Rand_log_event
  Rotate_log_event (partial)
sql/sql_class.h:
  Fixed typo in comment.