Replaced uses of counted_t<val_t> with scoped_ptr_t<val_t> everywhere.
Merge branch 'next' into sam_scoped_val
Made val_t not inherit from single_threaded_countable_t.
Merge branch 'next' into sam_scoped_val

Conflicts:
	src/rdb_protocol/terms/obj.cc
	src/rdb_protocol/terms/obj_or_seq.cc
Merge branch 'sam_scoped_val' into next