By Caldwell Titcomb Note: Rusalka is transferring to the West End’s London Coliseum from March 28 to April 15, 2020. Czech opera is not often mounted in these parts. The two major composers were Bedrich Smetana (1824-84) and Antonín Dvořák (1841-1904). The latter wrote ten operas, some comic and some tragic. Among Czech natives, the…