Re-add in simple scheduler for compatibility with legacy code, mark all scheduler related files as deprecated.

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.

Better documentation for the MissleLauncher project - add credit to PyLauncher project.

Remove ConfigDescriptor.c/.h files from the ClassDriver Host demos, as they will be obsoleted when the Host mode class drivers are complete. Add new StillImage stub class driver common header.

Enhanced class drivers to use the same public/private section seperations as other portions of the library.

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.

Copy over schedulerless host demos to ClassDrivers directory, for later modification to new Host mode USB class drivers.

Deleted Host ClassDriver demos -- not yet started, faster to rebase new ClassDriver demos from the newly schedulerless LowLevel host demos rather than re-convert each demo from the previous scheduler-based implementations.

Fixes to MassStorageHost demo to improve compatibility with more USB drives.