Add new option to ignore match threshold for partial matches

[ojalaquellueva]

If a species name cannot be matched, the TNRS may still return a partial match on the genus. For some users this is a useful feature. However, because partial matches will generally have low overall match scores due to the unmatched epithets and possibly authors, the default match threshold of 0.53 often causes partial matches to be hidden, even when the partial match is a perfect match, at rank.

To address this issue, I suggest we add a new option "Allow partial matches below threshold". This would be a On/Off toggle button below the Sources option. Default setting would be off. If set to on, the match threshold filter would be applied only to results that do not contain the string "%partial%" in the plain English warning column. Partial matches would not be filtered.

[ojalaquellueva]

See related closed issue #105 for details.

[ojalaquellueva]

Just realized: this feature can only be implemented in TNRSweb interface, as it depends on the value of Match Threshold set by the user. It will require developing an alternative function which ignores match_threshold if warnings LIKE "%partial%" (or the equivalent integer values in the integer warnings columns; may run faster using an IN list of integer values).