Finish handling of JATS4R versions

[Klortho]

This is moved from here

This ticket is about JATS4R versions, as opposed to JATS versions.

Here's a survey of the places where versions show up:

• ✓done - The validator gets the list of versions form schema/versions.yaml
• ✓done - In the URL of our schema files. For example, "http://jats4r.org/schema/0.1/jats4r.sch". See JATS4R schema processing instruction. This is done, in that the validator reads that PI and uses the correct version.
• ✓done - In the corresponding location for the generated XSLTs. The validator has to know which version of our schema to use
• In the bin/process-schematron.sh script, which has to know where to get its input, and where to write its output.
• Tags in our GitHub repositories (both website and validator have to match). Whatever is in the repositories at that tag is, by definition, that version.
• The recommendations pages on our website should have a version number attached to them. See below.
• ✓done - In the validator: it has to be able to read the processing instruction, and select the appropriate XSLT files to run. See #51 .
• Update the wiki Workflows and procedures

Versioning of topics

All of our topics' recommendations pages move forward together. See Jeff's comment here.

Think about topics as like chapters in a book, with different editions. With a new edition, even if the chapter doesn't change, you can still refer to it with any edition number in which it appears.

Our website should have a complete set of the recommendations at each version, with an easy way of navigating between them, and also a set without a version number in the URL, that corresponds to the "current" or latest version.