Added SPI module pin definitions.
Configured SPI module pins SCK, MOSI and SS as output pins.
Renamed spi_transmitter.h/c to spi_master.h/c
initSPI(): Enabled SPI module and configured chip using this code as the SPI MASTER. Also rewrote comment/documentation for SPI power reduction; that doesn't enable the SPI module so much as ensure that it will work by being powered on.