New name resolution

To unlock some impossible now features like dependent subqueries in a FROM clause name (but probably not only this) resolution should be redone to separate it from other info collecting.

• First pass should create array of name of fields (Item_type_holder) for SELECTs and TABLE_LISTs, including unfolding "*" in SELECTs (inner -> out, Post-order tree traversal) (actually it would be better to have just iterators fr fields, so it is not needed)
• Second pass (or two) only create connection between place of name usage (Item_ident) and a field descriptor in the table above (possible in any order now) (can be done by pre-made on parser list of names which need to be resolved)
• Third pass collect type information for all Items, calculate type compatibility (Post-order tree traversal).
• Fourth pass "normalize" tree:
  • add correct Item in place of resolved names
  • constant calculation/conversion
  • ...

All changes made once and on statement mem_root memory.