change # 147 -> 127 to use up barcode # holes;
use "common.h" funcs `str_to_uppercase()` -> `to_upper()`,
`count_char_occurrences()` -> `chr_cnt()`;
prefix defines with `DX_` and funcs with `dx_`;
`ZINT_DEBUG_PRINT` -> `symbol->debug & ZINT_DEBUG_PRINT`;
bools to ints; use `posn()` to check for slash (returns length);
restrict line lengths to 118; suppress some clang-tidy warnings;
normalize some error messages;
check for single "A" if any (`sscanf()`);
use compliant height default; some whitespace formatting;
Tcl: add DXFILMEDGE support
docs: document DXFILMEDGE; update to latest pandoc
test suite: ZXingCPP: DXFILMEDGE support
