* Remove parameters/append that are never outputted by texvc.ml
* Add missing math_output_error to i18n file
* Improve a few qqq descriptions
Change-Id: Iea5139682fbe8389e578549f5f62e5505f4c0b48
Physikerwelt asked for some guidance on how to write good unit tests for
classes that depend on external resources. I wrote a few to serve as examples
for additional tests. Because they have an ulterior didactic purpose, the
comments are a bit more verbose than I would otherwise like, but despite that
the tests are good enough to merit being merged.
Change-Id: Ifa97eec1a68fb68b4744d1e5b192b410afe5ef68