evolve: extract displayer to _solveone() I extracted this displayer method to _solveone() so that it would be easy to pass a different template to show evolve msgs. In upcoming patches we will be using stacktemplate in some cases where we want to include stack alias s# in evolve msgs.

test-drop.t
test-inhibit.t
test-simple4server.t
tests/test-simple4server-bundle2.t