sql/item.h:
  constructor and method for aloning AND/OR structure of WHERE clause
sql/item_cmpfunc.cc:
  constructor and method for aloning AND/OR structure of WHERE clause
sql/item_cmpfunc.h:
  constructor and method for aloning AND/OR structure of WHERE clause
sql/item_func.cc:
  constructor for aloning AND/OR structure of WHERE clause
sql/item_func.h:
  constructor for aloning AND/OR structure of WHERE clause
sql/sql_lex.cc:
  field for saving WHERE root
sql/sql_lex.h:
  field for saving WHERE root
sql/sql_prepare.cc:
  saving WHERE root
  creating new AND/OR structure before executing prepared statement
tests/client_test.c:
  test suite for bug #1180