Makefile: Fix behavior when modifying src/target/ACTIVE
LAN8720: Wait for 10 milliseconds after reset before talking to the chip, otherwise it might become upset.
STM32: Fix DMA register definitions on F1 chips
STM32: Fix GPIO::getLevel to always return 0 or 1, instead of zero an nonzero values.
STM32: ETHMAC: Don't disable clock gates on F1 chips, add MDC/MDIO bitbanging support to work around F1 pinmux/AFIO limitations.
ArtNetNode: Fix things to make it actually work on F107 boards as well.
Only DMA UARTs are supported so far, the PIO-only UART needs some further work.