escape trailing '?' on all PCREs in formats file
escape trailing '?' on all PCREs in formats file

Escape the end sentinel ('?'), which changes the matching behavior of
the formats file PCREs.  Previously, some cards were mismatched, such as
the petro_points example, which libbitconvert claimed was an "M&M Meat
Shops MAX card".  This change fixes such mismatches.

ossguy/libbitconvert