Escaping, table layout, and document fixes

Quoted Klammertext specials (^@ ^| ^# ^^ ^: ^*) and ^'...'^ regions now
survive re-processing (held as escape markers until final output);
:after_apply phase functions receive and return raw target text.

Tables: :hpos element position (center|left|right|<length>) replaces the
unimplemented :center/:indent; the ranged cell override is renamed
:justify; :column_width works in html (colgroup widths) and gains
'fill' -- the remaining width, capped at the column's widest entry, in
both targets; a table wider than the text column warns on the console;
table edges without an outer line set their text flush on the margins.

@document: no empty title bar for untitled documents; @vfill fills to
the bottom of the window in html (pure CSS); @vspace in plain text;
new @dot klammer; monospace email links.

sks/table/sty/table.sty

@@ -28,3 +28,11 @@
 
 \newsavebox{\tablebox}
 \newlength{\tableboxwidth}
+
+% Computed widths of :column_width 'fill' columns (up to four per table):
+% min(share of the remaining width, widest entry), set per table in the
+% generated LaTeX via calc's \minof/\ratio.
+\newlength{\klfilla}
+\newlength{\klfillb}
+\newlength{\klfillc}
+\newlength{\klfilld}