firmware: newline at end of spi.h
Add USB host and joystick functions

These are copied from these repos:
https://github.com/eecsninja/USB_Host_Shield/ (branch duinocube)
https://github.com/eecsninja/USBJoystick (branch master)
Add ch9.h to usb
firmware/usb: Fix #include style/order
firmware: Create separate timer module

Move the file system timer there.
Also add a millisecond timer counter.
firmware: Add USB module with joystick support
firmware: USB host controller uses timer module
arduino: RPC support for USB and joystick