item types was removed some time ago. Simplify.
(VT_ITEM, VT_TYPE, V_MAX): Unused, remove.
(show_sect_capab): Properly use ichr[] member i_mnem to print item
characters.
Simplify. Split into member sct_che (number) and sct_che_target.
Users changed.
(get_che_cnum, set_che_cnum, get_che_value, get_che_value): Che
encoding/decoding functions; remove.
(CHE_MAX): Move from var.h to sect.h.
(prsect, doland): Print / edit the new field.
To save space, the ancients invented `variables': a collection of
key-value pairs, missing means zero value, space for `enough' keys.
This complicates the code, as assigning to a `variable' can fail for
lack of space. Over time, `enough' increased, and for quite some time
now `variables' have been *wasting* space. This changeset replaces
them, except in struct mchrstr, struct lchrstr and struct pchrstr,
where they are read-only, and will be replaced later. It is only a
first step; further cleanup is required. To simplify and minimize
this necessarily huge changeset, the new item[] arrays have an unused
slot 0, and the old variable types V_CIVIL, ... are still defined, but
must have the same values as the item types I_CIVIL, ...
