Add crate-level doc comment

src/lib.rs

@@ -1,3 +1,19 @@
+//! Low-level Rust bindings for libburn.
+//! 
+//! You can find out more about the libburnia project, of which libburn is a part, by visiting
+//! <https://dev.lovelyhq.com/libburnia/web/wiki>
+//! 
+//! This version of libburn-sys is based on libburn 1.5.6
+//! 
+//! ## Requirements
+//! 
+//! Currently, libburn-sys does not support statically linking libburn into your application, and may never do.
+//! Instead, **you must have libburn 1.5.6 or greater installed** on your system so libburn-sys can dynamically
+//! link to it.
+//! 
+//! Bindings for libburn are pregenerated for libburn-sys, so you shouldn't need bindgen's dependencies
+//! installed to start using libburn-sys.
+
 /* automatically generated by rust-bindgen 0.72.1 */
 
 #[repr(C)]