Implement Send to allow for shared state

Signed-off-by: Aron Heinecke <aron.heinecke@t-online.de>

src/core.rs

@@ -28,6 +28,8 @@ pub struct Instance {
     pub(crate) ptr: *mut sys::libvlc_instance_t,
 }
 
+unsafe impl Send for Instance {}
+
 impl Instance {
     /// Create and initialize a libvlc instance. 
     pub fn new() -> Option<Instance> {

src/media.rs

@@ -12,6 +12,8 @@ pub struct Media {
     pub(crate) ptr: *mut sys::libvlc_media_t,
 }
 
+unsafe impl Send for Media {}
+
 impl Media {
     /// Create a media with a certain given media resource location, for instance a valid URL. 
     pub fn new_location(instance: &Instance, mrl: &str) -> Option<Media> {

src/media_player.rs

@@ -15,6 +15,8 @@ pub struct MediaPlayer {
     pub(crate) ptr: *mut sys::libvlc_media_player_t,
 }
 
+unsafe impl Send for MediaPlayer {}
+
 impl MediaPlayer {
     /// Create an empty Media Player object
     pub fn new(instance: &Instance) -> Option<MediaPlayer> {