Fix issue #41 by making sure all steps have a primary output.
Fix issues #1 and #17
Per minutes of 5 Nov, make it explicit that at most one document can appear on the p:xslt result port.
Merge pull request #106 from ndw/xslt-fixes

Fix issues #1 and #17
Merge pull request #105 from ndw/primary-outputs

Fix issue #41 by making sure all steps have a primary output.
Merge branch 'xproc20' of https://github.com/xproc/specification into xproc20