merging with switching on static tables optimization (SCRUM)
fixed subselects with uncacheable results
added test for fixed bugs from bugreports


mysql-test/r/subselect.result:
  changes in subselect test after switching on static tables optimization
  fixed bug test added
  uncacheable subselects
mysql-test/t/subselect.test:
  changes in subselect test after switching on static tables optimization
  fixed bug test added
  uncacheable subselects
sql/item_create.cc:
  fixed subselects with uncacheable results
sql/item_func.cc:
  fixed subselects with uncacheable results
sql/item_subselect.cc:
  fixed subselects with uncacheable results
  clean up
sql/item_subselect.h:
  fixed subselects with uncacheable results
sql/sql_lex.cc:
  fixed subselects with uncacheable results
sql/sql_lex.h:
  fixed subselects with uncacheable results
sql/sql_select.cc:
  fixed bugs in temporary tables in subselect implementation
  fixed subselects with uncacheable results
sql/sql_union.cc:
  fixed subselects with uncacheable results
sql/sql_yacc.yy:
  fixed subselects with uncacheable results