- If USER is given, all threads for that user is signaled
- If SOFT is used then the KILL will not be sent to the handler. This can be used to not interrupt critical things in the handler like 'REPAIR'.

Internally added more kill signals. This gives us more information of why a query/connection was killed.
- KILL_SERVER is used when server is going down. In this case the users gets ER_SHUTDOWN as the reason connection was killed.
- Changed signals to number in correct order, which makes it easier to test how the signal should affect the code.
- New error message ER_CONNECTION_KILLED if connection was killed by 'KILL CONNECTION'. Before we got error ER_SHUTDOWN.

Changed names of not used parameters KILL_QUERY & KILL_CONNCTION to mysql_kill() to not conflict with defines in the server


include/mysql.h.pp:
  Updated file
include/mysql_com.h:
  Changed names of not used parameters KILL_QUERY & KILL_CONNCTION to mysql_kill() to not conflict with defines in the server
mysql-test/r/kill.result:
  Added test of KILL USER
mysql-test/suite/rpl/r/rpl_stm_000001.result:
  Updated error code
mysql-test/suite/rpl/t/rpl_stm_000001.test:
  Updated error codes
mysql-test/t/flush_read_lock_kill.test:
  Updated error codes
mysql-test/t/kill.test:
  Added test of KILL USER
plugin/handler_socket/handlersocket/database.cpp:
  Removed THD:: from KILL
sql/debug_sync.cc:
  Removed THD:: from KILL
sql/event_scheduler.cc:
  Removed THD:: from KILL
sql/filesort.cc:
  Removed THD:: from KILL
sql/ha_ndbcluster_binlog.cc:
  Removed THD:: from KILL
sql/handler.cc:
  Removed THD:: from KILL
  Simplify code.
sql/lex.h:
  Added new keywords HARD | SOFT
sql/log.cc:
  Removed THD:: from KILL
  Added testing of new error ER_CONNECTION_KILLED
sql/log_event.cc:
  Removed THD:: from KILL
  Added testing of new error ER_CONNECTION_KILLED
sql/mysql_priv.h:
  Added new prototypes
sql/mysqld.cc:
  Removed THD:: from KILL
  Use KILL_SERVER_HARD signal on shutdown.
sql/scheduler.cc:
  Removed THD:: from KILL
  Simplify test if connection should be killed
sql/share/errmsg.txt:
  New error message ER_CONNECTION_KILLED
sql/slave.cc:
  Removed THD:: from KILL
sql/sp_head.cc:
  Removed THD:: from KILL
sql/sql_base.cc:
  Removed THD:: from KILL
sql/sql_cache.cc:
  Removed THD:: from KILL
sql/sql_class.cc:
  Removed THD:: from KILL
  Added killed_errno()
  Only signal kill to storage engine if HARD bit is set.
sql/sql_class.h:
  Move KILL options out from THD to make them easier to use in sql_yacc.yy
sql/sql_connect.cc:
  Removed THD:: from KILL
sql/sql_delete.cc:
  Removed THD:: from KILL
sql/sql_error.cc:
  Removed THD:: from KILL
sql/sql_insert.cc:
  Removed THD:: from KILL
  Simplifed testing if thread is killed.
sql/sql_lex.h:
  Added kill options to st_lex
sql/sql_load.cc:
  Removed THD:: from KILL
sql/sql_parse.cc:
  Added kill options to st_lex
  Simplifed and optimzed testing of thd->killed at end of query
  Added support for KILL USER
  Extended sql_kill() to allow use of more kill signals.
sql/sql_repl.cc:
  Removed THD:: from KILL
sql/sql_show.cc:
  Removed THD:: from KILL
  Simplied testing if query/connection was killed
sql/sql_table.cc:
  Removed THD:: from KILL
sql/sql_update.cc:
  Removed THD:: from KILL
sql/sql_yacc.yy:
  Added support for new KILL syntax: KILL [HARD|SOFT] [CONNECTION|QUERY] [ID | USER user_name]
storage/archive/ha_archive.cc:
  Simplify compilation
storage/maria/ha_maria.cc:
  Removed THD:: from KILL