Fixed GStreamer error printing and added option to disable sending cover

art to Discord RPC (Security issue)

GStreamer's GError is a struct, not a char*, with GError->message being
the actual char* message.

Since Subsonic/OpenSubsonic servers don't have a way of sending cover
art unauthenticated, sending cover art to Discord using Discord RPC
exposes an authenticated URL to Discord servers (But only Discord since
it is then proxy'd). Added a config option to disable this behavior and
only use the app icon if the user doesn't feel comfortable enough to
trust Discord (understandable tbh)

src/player/player.c

@@ -51,7 +51,7 @@ static gboolean gst_bus_call(GstBus* bus, GstMessage* message, gpointer data) {
             gchar* debug;
             GError* error;
             gst_message_parse_error(message, &error, &debug);
-            printf("Gstreamer Error: %s\n", error);
+            printf("Gstreamer Error: %s\n", error->message);
             g_error_free(error);
             g_free(debug);
             break;
@@ -150,7 +150,9 @@ void* OSSPlayer_ThrdInit(void*) {
             discordrpc->songLength = songStruct->duration;
             discordrpc->songTitle = strdup(songStruct->title);
             discordrpc->songArtist = strdup(songStruct->artist);
-            //discordrpc->coverArtUrl = strdup(coverart_url->formedUrl);
+            if (configObj->discordrpc_showCoverArt) {
+                discordrpc->coverArtUrl = strdup(coverart_url->formedUrl);
+            }
             discordrpc_update(&discordrpc);
             discordrpc_struct_deinit(&discordrpc);