+ spi_transmission_done(): Made it point to the right bit in status
register (bugfix).
+ spi_write(): Made it use the mask that existed from earlier.
+ spi_rx_ready(): Made it return a 1 if true and 0 if false.
+ spi_tx_ready(): Made it return a 1 if true and 0 if false.
spi_read(): Made it use a mask that existed from earlier in spi_2.c
+ spi_software_reset(): Wrote this function in spi_2.c
+ spi_selector_close(): Wrote this function in spi_2.c