Add Helpful toString methods and other ammenities

[Tyler-Lentz]

Currently there aren't really any nice ways to display packet information to a string.

It would be cool if there was a function along the lines of

void packetToString(packet_t packet, const char* out, size_t out_len);

which wrote string data to out, stopping at out_len bytes.

If we updated the obc networking code to use c++ instead of c (which we should do) this could just return an std::string