Serialport Support

- allow communication to elm327 device via a serialport
- allow creation of elm327 device without requiring unwrap()
- added some extra documentation
- expose reset() functionality of device
- serial_comm and ftdi_comm abstractions added

src/lib.rs

@@ -6,14 +6,20 @@
 //!
 //! # Usage
 //! ```
-//! use obd2::{commands::Obd2DataRetrieval, device::Elm327, Obd2};
+//! use obd2::{commands::Obd2DataRetrieval, device::{Elm327, FTDIDevice}, Obd2};
 //!
 //! fn main() -> Result<(), obd2::Error> {
-//!     let mut device = Obd2::<Elm327>::default();
+//!     let mut device = Obd2::new(Elm327::new(FTDIDevice::new()?)?)?;
 //!     println!("VIN: {}", device.get_vin()?);
 //!     Ok(())
 //! }
 //! ```
+//!
+//! alternatively, you could use a serial port provided by your operating system such as
+//! /dev/ttyUSB0 on unix-like systems
+//! ```
+//! let mut device = Obd2::new(Elm327::new(SerialPort::new("/dev/ttyUSB0")?)?)?;
+//! ```
 
 #![forbid(unsafe_code)]
 #![warn(missing_docs, clippy::panic)]