Changes to work with Saxon 9.9 (but not Saxon 10).

[tgraham-antenna]

If not using a Saxon config file, the initializer needs to be specified on the Saxon command line with -init:ConnectorSaxon9apiInitializer.

Someone who understands Maven better than I do should somehow fix pom.xml so that it's possible to build both forms of Saxon extension at once.

[c-alpha]

It seems that this PR does what the DITA-OT Implementing Saxon extension functions manual describes for Saxon 9, i.e. will make xslthl usable in a DITA-OT plugin again?

[tgraham-antenna]

It works well enough for me where I run Saxon on the command line. YMMV.

This PR probably should not be merged as-is because it stops the existing SaxonB version from building.

I am not familiar with the DITA-OT technique of using <service> elements in an Ant build file, so I can't say how this PR relates to that technique.

[c-alpha]

[...]
This PR probably should not be merged as-is because it stops the existing SaxonB version from building.
[...]

http://saxon.sourceforge.net Saxon B is officially in "deep freeze" state, so I would speculate that the number of users affected by removing support for it will likely be very limited.