This resolves an old bug reported by David Edmondson in 2014. The fix
is only needed for the "boolean" case, as probabilistic / phrase
searching already ignores punctuation.
This fix is only for the infix (xapian provided) query parser.
[1]: id:cunoasuolcv.fsf@gargravarr.hh.sledj.net
The main goal is to allow configuration information to be temporarily
overridden by a separate config file. That will require further
changes not in this commit.
The performance impact is unclear, and will depend on the balance
between number of queries and number of distinct metadata items read
on the first call to n_d_get_config.