IO_PCA9555.h added changes that had been applied to IO_MCP23017 for support on PCA9548 Mux. Constructor now also private and type casting of variables made the same for IO_PCA9555. Tested with MCP23017 and PCA9555 simultaneous on the same Mux Subbus
Updated Class PCA9555 definition reflecting changes in IO_MCP23017.h to support PCA9548 mux. Checked with PCA9555 base board, compiles and run EXRAIL script with output driver