Change separator for ITS annotatorsRef to use white-space not space

[ysavourel]

The ITS specification is not clear on this. But the Schematron rules use white-space, and it does allow wrapping. If we allow only ASCII space we cannot wrap and that is bound to get us errors.

[ysavourel]

The separator for the annotatorsRef values is now '\s' (white-space). This resolves issue #612.

→ <<cset ae8f25a3820e>>