Since checking table compatibility before locking the table, there were
potential that a table could be locked that did not have a definition
that was compatible with the table on the slave.

This patch adds a check just after the table was locked to ensure that
the table is (still) compatible with the table on the slave.


sql/log.cc:
  Moving placement new operators to slave.h since they are used in
  several places in the replication code.
  Removing some compile warnings.
sql/log_event.cc:
  Moving code to check table compatibility to after tables are locked for
  writing.
sql/log_event.h:
  Doxygenifying comments.
  Copying error codes to Rows_log_event hierarchy since they are
  now used there as well.
sql/rpl_utility.h:
  Doxygenifying some comments.
  Changing class table_def to copy the column types given to it.
  Adding structure RPL_TABLE_LIST as a subclass of TABLE_LIST to represent
  lists of tables for the slave.
sql/slave.h:
  Adding placement new and delete operators since the slave uses them
  in several places.
sql/sql_insert.cc:
  Removing a compiler warning.