Litan Virgil / Sabertooth

Library for Sabertooth motor driver ported from the oficial Arduino library. Packetized Serial Mode

I ported the official arduino library for Sabertooth dual motor drivers. In the porting process I did not used const methods as the original library does, but the functionality stays the same. I also added some methods that I find useful. According to the documentation of the driver this code should be compatible with SyRen drivers.