* Cleaned-up code.
 * Added back support for mass storage mode
 * Joystick mode selected when switch SA is UP, otherwise mass storage mode is active
 * using same USB device descriptor for MSC and HID mode, it works (at least on Linux)
Decided to use different USB PID for mass storage and joystick mode. It is safer and enables usage of device filters (for example on Virtualbox). Description strings are also different.