Bruce Davison is one of Hollywood's hardest-working "chameleons", having turned in dozens of outstanding performances in both lead and character roles on stage, screen and television. During his 30-plus-year career he has played many a villain and hero--tackling the roles of disturbed teenagers, crusading defense attorneys, romantic lovers and put-upon husbands. He has managed to avoid being typed, or when typed, the tag has not stuck long. Though some still identify him with the nerd who kissed the rodent in "Willard" (1971), others may remember him as Captain Wyler from NBC's "Hunter