'...&MATCH_SCORES=1,-3&...' will set
match to 1 and mismatch to -3
Note: The default will be used if this parameter was not explicitly
specified in the put URL. It supersedes the 'NUCL_REWARD'
and 'NUCL_PENALTY'. The restriction on input
values to the old parameters also applies to MATCH_SCORES.
See 6.13.1.