Added rustii CLI wad edit command and required library features

This required a LOT more backend work than I expected. But hey, some of this stuff is being done better than it was in libWiiPy/WiiPy, so that's a win in my book.
When changing both the Title ID and type of a WAD, the updated TID will only be written once (which also means the Title Key will only be re-encrypted once). This is an improvement over WiiPy where it will be updated as part of both changes.
Some TMD fields have been made private and moved to getter/setter methods only as they are actually in use now and should only be set through the correct means.

src/bin/playground/main.rs

@@ -7,7 +7,7 @@ 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));
+    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());