Sia is the musical genius behind the hit songs “Diamonds” (Rihanna), “Titanium” (David Guetta), “Let Me Love You” (Ne-Yo), “Radioactive” (Rita Ora) and “Pretty Hurts” (Beyonce). After stepping out of the limelight in 2010 she has returned with her sixth studio album. “1000 Forms Of Fear” is easily Sia’s strongest collection of work and is the…