[Mod] World Downloader [1.6.4]

Using new launcher (Replace 1.x.x with 1.6.4, etc in these instructions):
Note: If you have a recommendation for simplifying these, I'm all ears. Don't just say MAKE IT FORGE COMPATIBLE. Forge does not have the hooks for directly capturing network and screen events.

Close the launcher.
Copy the .minecraft/versions/1.x.x folder to .minecraft/versions/1.x.x.wdl
Go into folder 1.x.x.wdlRename 1.x.x.jar to 1.x.x.wdl.jar
Rename 1.x.x.json to 1.x.x.wdl.json
Edit 1.x.x.wdl.json and replace text "1.x.x" with "1.x.x.wdl"
Open 1.x.x.wdl.jar, delete META-INF and copy in the class files from the World Downloader zipfile.
Restart the launcher, "edit profile" (or make a new profile) and "use version" 1.x.x.wdl.