Offer-motivated features: :hline defaults, ranged :hpos, @date :days, :bottom none

- @table: a writer's :hline/:vline replaces the default lines; new
  boundary name 'none' removes all lines
- @table: ranged :hpos argument overrides :cell_hpos per cell
  (\multicolumn{1} in tex; positions a colspan anchor's merged cell)
- @date/@datetime: :days offset argument (sks/date/date.py)
- @document: ":bottom none" suppresses the footer (\pagestyle{empty})

Also carries the escape-system generator/renderer fixes, per-cell-range
:format, and uppercase .TTF/.OTF font recognition from klammertext-dev.

mac/klammer.h

@@ -86,6 +86,9 @@ public:
     std::map<std::string, Locator> m_defloc {}; // target -> Locator
     std::map<std::string, defmode_t> m_defmode {}; // target -> defmode
     target_variable_map_t m_varmap {}; // target -> map: variable -> index
+    // target -> true if this target's body came from a general ("*") definition
+    // (writer content, subject to target escaping) vs a target-specific one.
+    std::map<std::string, bool> m_body_generic {};
 };
 
 std::string klammer_name_from_katom(std::string s, Locator loc);