During testing of the NVRAM Switch changes (#451), I found some pre-existing stuff I didn't like, so I have tried to clean things up.
- BOOT_DEFAULT has been replaced by AUTO_CMD
- There is no longer a "default" boot loader command when pressing <enter>.
- Detect CTS at startup to ensure it is asserted. If not, disable hardware flow control to avoid stalling the console at boot. Only for UART driver because this is the only place it is currently relevant.
- FD driver will now detect presence of FDC hardware and install if found in all standard configurations
- Does *not* detect type of FDC which must still be set in config
- Added default FD driver MODE to all configs
- Thanks to Alan Cox for the technique!
