Clean up sha-1 and start with md4 implementation

src/main.rs

@@ -3,6 +3,7 @@ mod bytes_base64;
 mod cbc;
 mod ctr;
 mod ecb;
+mod md4;
 mod mt19937;
 mod mtcipher;
 mod parser;
@@ -47,6 +48,8 @@ fn main() {
         set4::challenge29();
         set4::challenge30();
     } else {
+        set4::challenge28();
+        set4::challenge29();
         set4::challenge30();
     }
 }