Minor fixes

frontends/moa-minifb/src/bin/moa-genesis.rs

@@ -7,7 +7,7 @@ use moa::machines::genesis::{build_genesis, SegaGenesisOptions};
 fn main() {
     let matches = moa_minifb::new("Sega Genesis/Mega Drive Emulator")
         .arg(Arg::new("ROM")
-            .help("ROM file to load (must be flat binary)"))
+            .about("ROM file to load (must be flat binary)"))
         .get_matches();
 
     let mut options = SegaGenesisOptions::new();

frontends/moa-minifb/src/lib.rs

@@ -11,7 +11,7 @@ use moa::error::Error;
 use moa::system::System;
 use moa::devices::Clock;
 use moa::host::traits::{Host, HostData, ControllerUpdater, KeyboardUpdater, WindowUpdater, Audio};
-use moa::host::controllers::{ControllerDevice};
+use moa::host::controllers::ControllerDevice;
 
 use moa_common::audio::{AudioOutput, AudioMixer, AudioSource};
 
@@ -183,7 +183,7 @@ impl MiniFrontend {
             controller,
             keyboard,
             audio: None,
-            mixer: mixer,
+            mixer,
         }
     }