For matches with no recommendation, import as-is or skip automatically.

Add `import: none_rec_action` setting with a default of "ask" (current
behaviour). If set to "asis" or "skip", matches with no recommendation will be
imported as-is or skipped automatically.
Add docs for `none_rec_action` setting.
Merge pull request #77 from mrmachine/none-rec-action

For matches with no recommendation, import as-is or skip automatically.