UTF-16LE, GBK, separate GB18030, UTF-32BE, UTF-32LE
add examples to tests for DATAMATRIX, HANXIN, QRCODE
HANXIN: Remove alternating filler in function information;
GB 18030 now ECI 32 (previously used ECI 29);
fix gate-posts on codeword limits
use new ZXing-C++ HanXin detector (diagnostics2 branch) for tests
check against ISO/IEC 20830:2021 (no substantive changes)
backend_tcl: update ECIs; NOTE: changed names "unicode" -> "utf-16be",
"euc-cn" -> "gb2312"
GRIDMATRIX/HANXIN/QRCODE/RMQR: warn if auto-conversion (i.e. no ECI given)
occurs to resp. specialized char sets (GB 2312/GB 18030/Shift JIS)
DMATAMATRIX: fix look ahead BASE256 use of dm_text_sp_cnt() on switching;
simplify dm_add_tail()
GUI: check suffixes on save so don't go into error state;
use native path for Save As clipboard message
CODE128: use gs1_check_digit() for NVE18 and EAN14
Rename barcode funcs to same as BARCODE_XXX name
library: barcode funcs array for dispatch, used for ZBarcode_ValidID() also
general: change is_sane() comparison to nonzero from ZINT_ERROR_INVALID_OPTION
MAILMARK: fuller error messages
CODABAR: add option to show check character in HRT
zint.h: use 0xNNNN for OR-able defines
GUI: add guard descent height reset button, add Zint version to window title,
static get_zint_version() method, use QStringLiteral (QSL shorthand),
use SIGNAL(toggled()), add errtxt "popup" and status bar, add icons,
add saveAs shortcut, add main menu, context menus and actions, add help,
reset_view() -> reset_colours(), add copy to clipboard as EMF/GIF/PNG/TIF,
lessen triggering of update_preview(), shorten names of getters/setters,
simplify/shorten some update_preview() logic in switch,
CODEONE disable structapp for Version S
qzint.cpp: add on_errored signal, add missing getters, add test
