By: Addison Wylie Life Itself has the sympathetic appeal and gravitas of a rightfully great documentary about an unbreakable legacy.  It’s the type of film Roger Ebert would’ve liked, even if it wasn’t chronicling the late film critic’s life and times. Ebert’s “thumbs up/thumbs down” signature alongside buddying rival Gene Siskel left more than just an imprint on the film industry.  Their clashing opinions and exuberance for winning movies had readers and viewers alike riveted….