use `tcolorbox` instead of `framed` for latex code blocks, works
much better, especially as now when using a background colour;
reduce gap after figures and force footnotes to bottom of page;
move most symbology figures to after some text to lessen chance
of subsection headers being orphaned on their own at end of page:
required a number of rewordings;
use named barcodes in example commands, rather than numbered;
fix "lua-crossrefs" filter to allow parentheses around
references;
various other fixes and rephrasings
some code fiddling on affected files
manual: use new lua filter "lua-crossrefs.lua" hacked from
https://github.com/rnwst/pandoc-lua-crossrefs as replacement for
tablenos which broke with pandoc 2.8.2 (get nicer output anyway);
fix "excode39.svg" data $ -> # to avoid shell processing;
document `ZBarcode_HaveGS1SyntaxEngine()`
creating "zint.dll" compatible with Windows XP (see ticket #339)
win32: rename README and HOWTO files to uppercase and update
"win32\README.txt"
general: suppress some VC6 warnings
README.bsd: update
GUI: fix chkGS1Strict enabling on startup regression from previous
commit; update CLI equivalence with --gs1strict & adjust for
implied --gs1; add tests
CMake: allow lpng/zlib and gs1encoders to take paths (for Windows)
win32/README: simplify locating lpng/zlib/gs1encoders for cmake
using above; add note on 64-bit build
manual/man page: adjust for various above changes
to get working using nmake "makefile.vcwin32", added to fork at
https://github.com/gitlost/gs1-syntax-engine;
small updates to Linux, macOS READMEs
GUI: change "chkGS1Strict" to be hidden instead of manually adding
pandoc: latest version
`DATA_MODE`); allows ZXing-C++ to be built in writer-only mode
without needing "libzueci"
library: in GS1 mode check that ECI if any is ASCII compatible
general: some code fiddling, `mode` -> `modes`
