Added WAD packing command to rustii CLI

Also added lots of required library magic to make WAD packing possible. This includes the high-level Title object from libWiiPy, the ability to set content in a WAD, the ability to generate a WADHeader from a WADBody, and more.

src/bin/playground/main.rs

@@ -2,9 +2,13 @@
 
 use std::fs;
 use rustii::title::{tmd, ticket, content, crypto, wad};
+use rustii::title;
 
 fn main() {
     let data = fs::read("sm.wad").unwrap();
+    let title = title::Title::from_bytes(&data).unwrap();
+    println!("Title ID from WAD via Title object: {}", hex::encode(title.tmd.title_id));
+    
     let wad = wad::WAD::from_bytes(&data).unwrap();
     println!("size of tmd: {:?}", wad.tmd().len());
     let tmd = tmd::TMD::from_bytes(&wad.tmd()).unwrap();