EAN/UPC: add quiet zone indicators option (API output_options

`EANUPC_GUARD_WHITESPACE`, CLI `--guardwhitespace`) (ticket #287)
EAN-2/EAN-5: HRT now at top instead of at bottom for standalones,
  following BWIPP
CLI: batch mode: don't close input if stdin
EAN/UPC: fix excess 1X to right of add-ons
Composites: fix excess whitespace; fix quiet zone calcs to allow
  for linear shifting
CLI: use own (Wine) version of `CommandLineToArgvW()` to avoid
  loading "shell32.dll"
Move "font.h" -> "raster_font.h"
EPS/SVG: use new `out_putsf()` func to output floats, avoiding
  trailing zeroes & locale dependency
EPS: simplify "TR" formula
SVG: change font from "Helvetica, sans serif" to "OCR-B, monospace";
  use single "<path>" instead of multiple "<rect>"s to draw boxes
  (reduces file size)
Add `EMBED_VECTOR_FONT` to `output_options` (CLI `--embedfont`) to
  enable embedding of font in vector output - currently only for
  SVG output of EAN/UPC
GUI: use "OCR-B" font for EAN/UPC and "Arimo" for all others (was
  "Helvetica" for both); paint background of screen preview light
  grey so as contrasts with whitespace and quiet zones
EMF: prefix funcs with `emf_`; simplify string `halign` handling
large: rename `large_int` -> `large_uint`
CODE128/common: move `c128_hrt_cpy_iso8859_1()` to
  `hrt_cpy_iso8859_1()` and add `ZINT_WARN_HRT_TRUNCATED` warning
  (for future use)
Various symbologies: replace `printf()` with `fputs()`
  (symbol->debug)
QRCODE: better assert(), removing a NOLINT (2 left)
CLI: add some more barcode synonyms for DBAR
common: various fiddlings
CMake: don't include png.c unless ZINT_USE_PNG (avoids clang
  warning)

docs/images/channel.svg

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