ISO/IEC 15420:2009 4.3.5 (and BWIPP) and adjust righthand outside
digit to be 4X/2X instead of 5X/3X (ISO/IEC 15420:2009
Annex A.2) away from main symbol so as not to touch add-on
TODO: revisit when standard clarified
remove legacy "T" prefix from def commands; reinstate previous R
(TR) def so as to use I (TB) copy to save file size, & for ULTRA
pre-group rects by colour to enable use; adjust H (TH) def so
can use new J copy to save file size; various other fiddles
manual: Royal Mail Mailmark - put Destination+DPS & RTS in tables
for readability