“Fasten your seatbelts; it’s going to be a bumpy night,” she declared as Margo Channing in “All About Eve.” Moviegoers were happy to go along for the ride when this bug-eyed spitfire was dealing out the bon mots.Never a beauty, Bette Davis managed to crash the Hollywood party with talent and sheer force of personality, dominating the late ’30s and ’40s with 10 Oscar nominations and two wins (for “Dangerous” and “Jezebel”) in a vast variety of roles, from bitches and prostitutes to virgins and mothers. Her best roles came because she fought for them. She lost a lawsuit to Jack Warner after she walked out on her contract, but then won the string of on-screen opportunities that changed her destiny. Easy to imitate, with her husky voice, ever-present cigarette puffing, disdainful slash of a mouth and drop-dead stare, she was impossible to duplicate. After fading away into drag-queen fodder, Davis fought her way to a comeback and gave some of her best performances in her 70s, before succumbing to cancer.