prioritise todo list a bit
add helper macros NFAI_HI_BYTE and NFAI_LO_BYTE
implement case-insensitive flag on match_byte_range
update the todo list
extend nfai_print_opcode to cope with multi-range character classes
extend nfai_print_opcode to print ranges with numbers as well as characters
fix nfa_build_match_byte_range: number of ranges was not being stored
fix nfa_build_match_byte_range: double-expanding a range didn't work