Palladium−Copper Catalyzed Synthesis of Benzofused Heterocycles with Two Heteroatoms: Novel and Highly Regio- and Stereoselective Syntheses of ( E )-2-(2-Arylvinyl)-3-tosyl-2,3-dihydro-1,3-benzothiazoles and ( E )-2-Alkyl(aryl)idene-3,4-dihydro-2 H -1,4-benzothiazines