Small schema update
Better error handling on xpath/multiplication

When one of the arguments is nil, we set it to 0 with an error message
Documentation / schema update
Disable orphan setting on the last line

Disabling orphans made the publisher ignore one line texts (such as titles).
The numbers are just for debugging purpose.
Experimental fix for 'remaining height' on Output

The last row was wrong. Let's hope this fixes it without side effects.
Bugfix for one-line head and orphan handing

The last fix for one-line heads prevented coupled paragraphs 
(textformat break-below="no")