- 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

backend/tests/data/svg/ean8_2addon.svg

@@ -30,18 +30,18 @@
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       <rect x="146.00" y="0.00" width="2.00" height="110.00" />
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-      <rect x="198.00" y="19.00" width="4.00" height="91.00" />
-      <text x="48.00" y="116.00" text-anchor="middle"
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+      <rect x="166.00" y="16.90" width="4.00" height="93.10" />
+      <rect x="174.00" y="16.90" width="4.00" height="93.10" />
+      <rect x="182.00" y="16.90" width="2.00" height="93.10" />
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+      <text x="49.00" y="116.10" text-anchor="middle"
          font-family="Helvetica, sans-serif" font-size="20.0" >
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       </text>
-      <text x="114.00" y="116.00" text-anchor="middle"
+      <text x="113.00" y="116.10" text-anchor="middle"
          font-family="Helvetica, sans-serif" font-size="20.0" >
          5670
       </text>