Verify that the PATH has been set up correctly

When creating copies with yabridgectl. This should at least give an
advance warning that some additional steps are required when first
setting up yabridge.

tools/yabridgectl/src/config.rs

@@ -56,7 +56,7 @@ pub struct Config {
 }
 
 /// Specifies how yabridge will be set up for the found plugins.
-#[derive(Deserialize, Serialize, Debug)]
+#[derive(Deserialize, Serialize, Debug, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]
 pub enum InstallationMethod {
     /// Create a copy of `libyabridge.so` for every Windows VST2 plugin .dll file found. After