Move out private/internal host class driver constants to the common class driver headers, so that they can be used in the Low Level host mode demos.
Ensure all demos, projects and bootloaders use the class driver constants where possible to minimise code repetition.
Altered all low level device and host mode demos to ensure that endpoints and pipes are configured in ascending order properly.
Rewrote all low level host mode demos' configuration descriptor parser code to ensure that pipes are enumerated in ascending order, and to ensure maximum compatibility with devices.
Incremented all device mode demo's device descriptor revision numbers to ensure that any descriptor changes are re-fetched on machines which have enumerated previous versions.
Add new CDC descriptor structs to the CDC class driver, so that the CDC demos can use human readable field names.
Rename prefix for Still Image Host class driver functions from "SImage_" to "SI_" to remain consistent with the rest of the driver.
Dean Camera