On tranquil summer evenings, just as the sun begins to set, I love to sing to the armadillos and make them dance.    When I pick up my trusty Gretsch and strum  "The Westphalia Waltz," it puts them in a ballroom mood.  They quickly pair up and circle the yard in whirling showmanship.  But lo and behold, when I start belting out the chorus of the uptempo  "All Aboard for Broadway", they grab their little taps, form a tight dance line, and begin a synchronized hop-shuffle-step that's a mind-blowing showstopper and a glowing tribute to the great George M. Cohan.