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/link/link.py

@@ -107,7 +107,7 @@ class Email(klammer_base.Klammer_base):
         if self.body:
             href += val("body", self.body)
         href = href[:-1]
-        result = '<a href="{}">{}</a>'.format(href, address)
+        result = '<a href="{}" class="monospace">{}</a>'.format(href, address)
         return result
 
     def tex(self):