Refs #29421

Cf. #24099

HttpUrlConnection by default sets an Accept header that includes HTML
which causes the TextGridRep frontend to display a landing page instead
of delivering the data. We now explicitely request XSLT there.

Fixes #24099

Refs #24099

Cf. #22310

Refs #22310

Refs #22310

Refs #22310

In Java 8, the built-in XSLTC produces invalid XML (containing a
namespace binding to the prefix `xmlns`, cf. #16730). Saxon however
cannot write to a StAXResult, so we need an adapter to SAXResult.

Fixes #16730.

TODO associated stylesheet is detected as a side effect of fetching the
source. Need to make sure this has been done when we call
getTransformer(). We also need a test here.

Refs #14397

Fixes #14397

Unlike frame.xsl this calls the transformation itself and thus does not
require a pipeline.

Fixes #14114

This reverts commit 427d4f0c.

Conflicts:
	src/main/webapp/WEB-INF/stylesheets/db2xhtml.xsl
	src/test/resources/11sqw.0.html
	src/test/resources/mjr3.0.html
	src/test/resources/mr23.0.html
	src/test/resources/mr47.0.html
	src/test/resources/msdd.0.html
	src/test/resources/n2kf.0.html
	src/test/resources/nbvb.0.html

Oh, this is all a hack. Why doesn't Firefox simply support display:
run-in?