Reorganise USB stack defines. Now config.h decides which class drivers get enabled...
treef9056ad1a886d1741b009a6d026b689e18040a17
drwxr-xr-x - apps
drwxr-xr-x - backdrops
drwxr-xr-x - bootloader
drwxr-xr-x - docs
drwxr-xr-x - firmware
drwxr-xr-x - flash
drwxr-xr-x - fonts
drwxr-xr-x - gdb
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drwxr-xr-x - rbutil
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