- Add text_gap option to allow adjustment of vertical gap between

barcode and text
- EMF/EPS/SVG/GUI: ignore BOLD_TEXT for EAN/UPC
- DAFT: up max to 250 chars
- EMF/EPS/SVG: fix addon bars placement/length when text hidden
- Qt backend: use `QFontMetrics::horizontalAdvance()` rather than
  `boundingRect()` to calc text width (seems to be more accurate)
- library: make printf/sprintf() format arg always literal string
- output: fix errtxt nos clash;
  use array for `out_upcean_split_text()` text parts
- raster/vector: smallify addon text printing logic
- frontend: warn if output file and direct options both given;
  add TODO note about `CommandLineToArgvW()` loading shell32.dll
- manual: put HRT options in own section

frontend_qt/mainwindow.h

@@ -69,9 +69,12 @@ public slots:
     void change_cmyk();
     void autoheight_ui_set();
     void HRTShow_ui_set();
+    void text_gap_ui_set();
     void dotty_ui_set();
     void codeone_ui_set();
     void structapp_ui_set();
+    void text_gap_zero();
+    void clear_text_gap();
     void on_encoded();
     void on_errored();
     void on_dataChanged(const QString& text, bool escaped, int seg_no);