TODO

   1
   2 Per database config.
   3
   4 Explain always returned even though database/path is wrong.
   5
   6 Control the various optimizations with config..
   7
   8 Live status (via search, present).
   9
  10 Possible threading.
  11
  12 Deal with Z39.50 options properly.
  13
  14 Deal with Z39.50 messages sizes properly.
  15
  16 Character set conversion for SRW queries.
  17
  18 Throw proper CQL conversion error.
  19
  20 Honor XPath.
  21
  22 Deal with scan, sort (throw diagnostic).
  23