Improve performance of Pipeline

[bertfrees]

This is just a reference to snaekobbi/issues#28. This way I'm adding the issue to SBS's to-do list. I have assigned it to me but note that I will be working on it on behalf of DAISY as well.

This also includes shortening the time it takes to run the test suite.

+1 from:

• NLB: Improve performance of Pipeline nlbdev/pipeline-mod-nlb#55
• Nota: Improve performance of Pipeline snaekobbi/pipeline-mod-nota#24
• Dedicon: Improve performance of Pipeline snaekobbi/pipeline-mod-dedicon#51

[bertfrees]

I updated the sbs branch to the latest xprocspec which has logging to file disabled. This had a really good effect on the dotify-formatter tests (on both the master branch and sbs branch) but unfortunately the sbs tests are still a problem (which suggests that for the sbs tests the logging wasn't the main issue).

[bertfrees]

This table lists the conversion times of test books provided by Mischa for different revisions:

		777d5f4	9654ef2	css:split in Java	(dirty)
short.xml	337	12s	12s
fiction_engel.xml	103K	30s (ERROR)	27s
nonfiction_natur.xml	670K	730s (ERROR)	281s (ERROR)		65s
fiction_haus.xml	865K		820s	83s	74s
nonfiction_vegeta.xml	866K		783s (ERROR)		(ERROR)
fiction_kuss.xml	969K		674s (ERROR)
fiction_grey.xml
fiction_arena.xml	2.8M	∞	2842s	166s

∞ = aborted process because took too long

[bertfrees]

After I fixed a memory leak in Calabash (daisy/xmlcalabash1@92a3460), the test suite finished again.