use cargo examples semantically

Cargo.toml

@@ -13,13 +13,8 @@ failure = "^0.1"
 libloading = "^0.5"
 num_enum = "^0.4"
 structopt = "^0.3"
-sdl2 = { version = "^0.32", optional = true }
-crossbeam-channel = { version = "^0.4", optional = true }
 
-[features]
-with-sdl2 = ["sdl2", "crossbeam-channel"]
-
-[[bin]]
-name = "example"
-path = "src/bin/example.rs"
-required-features = ["with-sdl2"]
+[dev-dependencies]
+# example: sdl2_emulator
+sdl2 = "^0.32"
+crossbeam-channel = "^0.4"

src/retro/wrapper.rs

@@ -255,7 +255,7 @@ impl StaticCallbacks {
                 };
                 Self::clone_into_void(data, &si)?
             }
-            // TODO EnvCmd::GetCameraInterface => {},
+            // TODO (apathy) EnvCmd::GetCameraInterface => {},
             EnvCmd::GetLogInterface => unsafe {
                 c_ext_handle_get_log_interface(data as *mut LogCallback)
             }
@@ -271,7 +271,7 @@ impl StaticCallbacks {
                 };
                 Self::clone_into_void(data, &pc)?
             }
-            // TODO EnvCmd::GetLocationInterface => {},
+            // TODO (apathy) EnvCmd::GetLocationInterface => {},
             EnvCmd::GetCoreAssetsDirectory => {
                 Self::path_into_void(data, handler.get_core_assets_directory()?)?
             }
@@ -307,7 +307,7 @@ impl StaticCallbacks {
                     .collect();
                 handler.set_controller_info(controller_info)
             }
-            // TODO EnvCmd::SetMemoryMaps => {},
+            // TODO (experimental) EnvCmd::SetMemoryMaps => {},
             EnvCmd::SetGeometry => {
                 handler.set_geometry(Self::from_void::<GameGeometry>(data)?.clone())
             }