urpc: Initial buggy draft

Signed-off-by: Andrew 'Necromant' Andrianov <andrew@ncrmnt.org>
urpc: initial rework and vusb transport

Signed-off-by: Andrew 'Necromant' Andrianov <andrew@ncrmnt.org>
rf24: Do not flush rx in rf24_stop_listening()

Signed-off-by: Andrew 'Necromant' Andrianov <andrew@ncrmnt.org>
rf24: Increase rf24_write timeout

Signed-off-by: Andrew 'Necromant' Andrianov <andrew@ncrmnt.org>