Move and rename DevChaper9.c/.h and HostChapter9.c/.h to the HighLevel directory, new named DeviceStandardReq.c/.h and HostStandardReq.c/.h.

Rename LowLevel.c/.h to USBController.c/.h.

Remove dependancies on the complete <avr/io.h> header in the HighLevel USB driver directory, to ensure less work is required in later (possible) ports.