Removed "Host_" section of the function names in ConfigDescriptor.h, as most of the routines can now be used in device mode on the device descriptor.

Renamed functions in the HID parser to have a "USB_" prefix and the acronym "HID" in the name.

Further module-level documentation updates.

Seperated out OTG, Device and Host mode demos into seperate folders for clarity. Adjusted makefiles so that the path to the LUFA library can be set in one place.