By Julio Martinez Laguna Playhouse announces its 99th season of shows. Its 2019-20 offering begins with the 1999 jukebox musical Mama Mia by Benny Andersson, Björn Ulvaeus (lyrics and music) and some songs by Stig Anderson, with book by Catherine Johnson,  originally conceived by Judy Craymer (July 7). Season continues with the premier of the comedy, Yoga Play, written by Dipika Guha (Sep …