Adds odd and even parity bit support to Soft::UAT and Soft::UART 

This PR adds (partial) support for odd/even parity bit to Soft::UAT and Soft::UART.
Soft::UAT is able to output the correct parity bit.
Soft::UART does not do checking for correct parity bit yet.
Oh, right, the parity bit is always the 9th bit in my code.
Should the initializing of data with stop bits and parity be done in putchar() or be done once in begin()?
I'm still not sure what to do if DATA9 is used though.