By Denny Dyroff, Entertainment Editor, The Times Selwyn Birchwood It may be a mid-week evening, but August 21 has several shows on its calendar that will get audiences out of their seats and dancing in the aisles – Selwyn Birchwood in Sellersville and Water Street in Philadelphia. Birchwood will bring his scorching blues sound to the Sellersville Theater (24 West Temple Avenue, Sellersville,...