This adds a `hackrf_debug [-S|--state]` option, and the necessary
plumbing to libhackrf and the M4 firmware to support it.
The USB API and libhackrf versions are bumped to reflect the changes.
These variables are already placed together; this commit just groups
them into a struct and declares this in a new header.
This commit should not result in any change to the firmware binary.
Only the names of symbols are changed.