More documentation and dead code disabling

lvgl/src/lv_core/obj.rs

@@ -1,3 +1,10 @@
+//! Native LVGL objects
+//! 
+//! Objects are individual elements of a displayed surface, similar to widgets.
+//! Specifically, an object can either be a widget or a screen. Screen objects
+//! are special in that they do not have a parent object and do not implement
+//! the `Widget` trait, but do implement `NativeObject`.
+
 use crate::lv_core::style::Style;
 use crate::{Align, LvError, LvResult};
 use core::ptr;

lvgl/src/widgets/mod.rs

@@ -1,4 +1,11 @@
-mod arc;
+//! Widget-specific features
+//! 
+//! Widgets represent individual elements on the screen. Each widget has
+//! associated information, namely its parent widget and its styling data. A
+//! widget with no parent will have a screen as its parent. Style data is
+//! inherited from parent objects by default.
+
+//mod arc;
 mod bar;
 mod label;
 mod meter;