Fixed bug where the CALS table preprocessing step wasn't being run.
Improved DocBook pipeline.

1. Gave it a type so that it can be imported and called.
2. Remove bogus ghost:* attributes.
3. Handle secondary outputs from the final-pass stylesheet (write them out)
Merge pull request #31 from ndw/master

Fixed catastrophic bug in handling of CALS tables. Also improved the docbook.xpl pipeline.