Auto-simplify the code with  gofmt -s.

Do a little auto-cleanup, based on gofmt.
Add "make lint" using gofmt -s and go vet.

Fix some additional errors discovered this way, most of which are with
builtin_actions_test.
conditions: Add new 'after' condition.

This condition becomes true after an inner condition remains true for
at least 'delay' time frame.

Readjust condition testing, slightly.