debug: First iteration

- Flesh out FPS counters and graph
- Add opacity slider
- Add specialized views
- Populate workspace state inspector (very basic)

src/main.rs

@@ -10,11 +10,13 @@ use slog::Drain;
 
 pub mod backend;
 pub mod input;
-pub mod rendering;
 pub mod shell;
 pub mod state;
 pub mod utils;
 
+#[cfg(feature = "debug")]
+pub mod debug;
+
 fn main() -> Result<()> {
     // setup logger
     let _guard = init_logger();