context and closing must accept multiple situations (answer too?)

rename "context"?

convert left/right -> L/R

impasse id=a1
impasse echo=a1 absent=right

merge prepare_* into a single command-line tool; move code into libraries

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rename "Dialog" to "Question and Answer"

   break the pattern

   even so, "answer" is the name of the attribute

   constraints -> seems to fit colloquial usage