Peripheral: GPIO: Fix xmega template.
Peripheral: GPIO: Beautify Software GPIO.
Tools: DFG: Add uart spi information to avr_io.
Tools: DFG: Do not parse USART_SPI.
Tools: DFG: Add USI, UartSpi and Timers to AVR device files.
Peripheral: Move Spi Mode enum class to interface.
Adapt implementations.
Peripheral: Add UartSpi master to AVR8 devices.