Add description to gltypes module

src/gltypes.rs

@@ -1,3 +1,13 @@
+///
+/// This module contains various type aliases and static function wrappers to
+/// make working with OpenGL cleaner and safer than working with the lmath types
+/// directly. This is especially important when working with type-sensitive OpenGL
+/// functions (such as `glVertexAttribPointer` and `glUniformMatrix4fv`) where a
+/// simple mistake such writing `Vec3::new(1, 2, 3)` or `Vec3::new(1f, 2f, 3f)`
+/// as opposed to `Vec3::new(1f32, 2f32, 3f32)` could cause you an afternoon of
+/// pain ("Where's my triangle!" he shouts in fustration).
+///
+
 pub use mat::{Mat2, Mat3, Mat4};
 pub use vec::{Vec2, Vec3, Vec4};
 pub use quat::Quat;