top: some minor tweaks to the utf-8 multi-byte support

top: some minor tweaks to the utf-8 multi-byte support

Translatable column headers are supposed to be limited
to no more than 7 characters, even though some columns
are wider than that or even variable width. That value
of 7 is dictated by the Fields Management screen which
will otherwise truncate a column header longer than 7.

Our new utf-8 support did not adequately deal with the
potential need for truncation of column headers should
that limit of 7 be exceeded. This patch corrects that.

[ a few comments were also tweaked just a little bit ]

Signed-off-by: Jim Warner <james.warner@comcast.net>