Added new "Common" section to the class drivers, to hold all mode-independant definitions for clarity.

Moved SCSI command/sense constants into the Mass Storage Class driver, instead of the user-code.

Break device mode class driver interfaces into seperate config and state structs which are then combined, for clarity. Move device mode class driver interfaces back into the device mode class driver headers from the common class headers to make room for host class interfaces.

Split out common defines/types from class drivers into a seperate common class driver directory.

Make central USB Class driver dispatch headers, used for both device and host modes.