unlink socket file if mysqld dies on startup
Some optimization of AND expressions


mysql-test/r/func_time.result:
  Update for new week() handling
mysql-test/t/func_time.test:
  Update for new week() handling
sql/item_cmpfunc.cc:
  Optimization of IF( and-expression,,)
sql/item_cmpfunc.h:
  Optimization of AND expressions
sql/item_timefunc.cc:
  Extended WEEK() to be able to handle ISO weeks.
sql/mysqld.cc:
  unlink socket file if mysqld dies on startup
sql/sql_base.cc:
  Fixed problem with SIGHUP and INSERT DELAYED
tests/Makefile.am:
  Added missing myisam-big-rows.tst file to source distribution