Show impl for machine

src/bin/main.rs

@@ -39,5 +39,7 @@ fn main() {
     }
 
     println!("Ran program, output of Accum is {}", machine.registers.accumulator);
+    println!("Machine dump: {}", machine);
+
 }
 

src/machine.rs

@@ -27,6 +27,7 @@
 
 use address::Address;
 use address::AddressDiff;
+use std::fmt;
 use instruction::Instruction;
 use instruction::ADC;
 use memory::Memory;
@@ -100,6 +101,12 @@ impl Machine {
     }
 }
 
+impl fmt::Show for Machine {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "I am a machine")
+    }
+}
+
 #[test]
 fn add_with_carry_test() {