“Cinderella” was an inspired choice for Jared Nelson’s first evening-length work as artistic director of California Ballet. The ballet, which premiered last weekend, continues the company’s tradition of going with classics that have family appeal and can fill the Civic Theatre. And, like Cinderella shaking off the ashes and emerging as a princess, Nelson’s lively choreography and sense of fun promise to reinvigorate the 50-year-old company’s sometimes-musty repertory.