Clean up before challenge 6.

src/main.rs

@@ -1,11 +1,12 @@
+mod base64bytes;
+mod hexbytes;
 mod set1;
 
-use crate::set1::challenge1;
-use crate::set1::challenge2;
-use crate::set1::challenge3;
-
 fn main() {
-    challenge1();
-    challenge2();
-    challenge3();
+    set1::challenge1();
+    set1::challenge2();
+    set1::challenge3();
+    set1::challenge4();
+    set1::challenge5();
+    set1::challenge6();
 }