Ignore empty catalogue numbers in ninjatune data, don't error out with old-style catno format
Filter barcodes better, by ignoring anything that doesn't look numbery
Merge branch 'mapping-import-fixes'

* mapping-import-fixes:
  Filter barcodes better, by ignoring anything that doesn't look numbery
  Ignore empty catalogue numbers in ninjatune data, don't error out with old-style catno format