add module doc str to file top

src/sdl2_gfx/framerate.rs

@@ -1,8 +1,9 @@
+//! Framerate control
+
 use libc;
 use libc::{c_void, uint32_t, malloc};
 use std::mem;
 
-
 mod ll {
     /* automatically generated by rust-bindgen */
 

src/sdl2_gfx/imagefilter.rs

@@ -1,3 +1,5 @@
+//! MMX image filters
+
 use std::cast;
 use std::c_vec::CVec;
 use libc;

src/sdl2_gfx/lib.rs

@@ -17,9 +17,6 @@ extern crate sdl2;
 #[link(name="SDL2_gfx")]
 extern {}
 
-
-//#[allow(non_camel_case_types, dead_code)]
-
 pub mod primitives;
 pub mod rotozoom;
 pub mod framerate;

src/sdl2_gfx/rotozoom.rs

@@ -1,3 +1,5 @@
+//! Surface Rotozoomer
+
 use libc::c_int;
 use sdl2::surface::Surface;
 pub use std::f64::consts::PI;