- Old sequence code forced row based replication for any statements that
  refered to a sequence table. What is new is that row based replication
  is now sequence aware:
   - NEXT VALUE is now generating a short row based event with only
     next_value and round being replicated.
   - Short row based events are now on the slave updated as trough
     SET_VALUE(sequence_name)
   - Full row based events are on the slave updated with a full insert,
     which is practically same as ALTER SEQUENCE.
- INSERT on a SEQUENCE table does now a EXCLUSIVE LOCK to ensure that
  it is logged in binary log before any following NEXT VALUE calls.
- Enable all sequence tests and fixed found bugs
- ALTER SEQUENCE doesn't anymore allow changes that makes the next_value
  outside of allowed range
- SEQUENCE changes are done with TL_WRITE_ALLOW_WRITE. Because of this
  one can generate a statement for MyISAM with both
  TL_WRITE_CONCURRENT_INSERT and TL_WRITE_ALLOW_WRITE. To fix a warning
  I had to add an extra test in thr_lock.c for this.
- Removed UPDATE of SEQUENCE (no need to support this as we
  have ALTER SEQUENCE, which takes the EXCLUSIVE lock properly.
- Removed DBUG_ASSERT() in MDL_context::upgrade_shared_lock. This was
  removed upstream in MySQL 5.6 in 72f823de453.
- Simplified test in decided_logging_format() by using sql_command_flags()
- Fix that we log DROP SEQUENCE correctly.
- Fixed that Aria works with SEQUENCE