Add a very simple example fetching properties

examples/fetch_state.rs

@@ -0,0 +1,15 @@
+use env_logger;
+use mpvipc::{Mpv, Error as MpvError};
+
+fn main() -> Result<(), MpvError> {
+    env_logger::init();
+
+    let mpv = Mpv::connect("/tmp/mpvsocket")?;
+    let meta = mpv.get_metadata()?;
+    println!("metadata: {:?}", meta);
+    let playlist = mpv.get_playlist()?;
+    println!("playlist: {:?}", playlist);
+    let playback_time: f64 = mpv.get_property("playback-time")?;
+    println!("playback-time: {}", playback_time);
+    Ok(())
+}