empty 08-rc.h.
move and rename rc methods.
RC_table.
File objects on longer use meta tag bits; added is_writable checks.
remove wc, mt fields from RC.
remove unused is_quotable; remove assert_ref_is_valid; add ref_counter_index.
update xcode project.
rename RC to RH.
remove inaccurate Tag, Sym types.
rename Struct_tag to Ref_tag.
remove packing on RH struct; change type to Uns to align.
comment.
remove sc (strong-count) from RH struct.
comments.
reorder obj type declarations.
type_sym distinguishes between DATA_WORD and DATA.
ref objects now carry type_sym instead of Ref_tag.