Auto add input element to programs that only contain text

[ascholerChemeketa]

Based on recent support discussion...

If a program lacks an input element around the text inside it, auto-supply the input. This tries to be very conservative and only does so if there are no other children in the parent element. (e.g. if you have a tests in the program you will not get an automatic input.)

I am quite sure that the XSL selection could be done better. Took this on as an XSL exercise, let me know how it should have looked. :)