Further polishing XSLT readme / instructions

[wendellpiez]

See notes on PR #46 (toward the end).

In addition to what is noted, the readmes etc. could use further careful edits for currency and correctness.

Wondering what (additional to the readmes) might help users learn how to use these, given the range of use cases. Part of the problem is that what the readme describes (command-line using freely available commodity tools) might be okay for demo/evaluation, but it is not an approach one is likely to use in actual production. Comments welcome.