The value of the actual argument of BIT-type-arg stored procedure was binlogged as non-escaped
sequence of bytes corresponding to internal representation of the bit value.
The patch enforces binlogging of the bit-argument as a valid literal: prefixing the quoted bytes
sequence with _binary.
Note, that behaviour of Item_field::var_str for field_type() of MYSQL_TYPE_BIT is exceptional
in that the returned string contains the binary representation even though result_type() of
the item is INT_RESULT.
* Allocate thd->user_var_events elements on appropriate mem_root
* If several SP statements are binlogged as a single statement, collect all user var
accesses they make (grep for StoredRoutinesBinlogging for details)
"Interleaved SPs execution is now binlogged properly, "SELECT spfunc()" is binlogged too.
The known remaining issue is binlogging/replication of "a routine is deleted while it is executed" scenario.
