She’s Beyoncé’s little sister, but has a style all of her own, and is now emerging as the one to watch in the fashion stakes. This month Solange Knowles was my standout choice for icon of the month for her interesting mix of  fabrics, styles and colours  that make her hypnotically watchable,  and totally unforgettable.   Solange has a gloriously groomed look that echoes 1970s Diana Ross crossed with 50s icon Dorothy Dandridge.   She flashes her wondrous legs in a series of showstopping dresses that just scream 1970s chic, but also looks amazing when she shows how to make androgyny a totally feminine look by adding heels and a…