Fix for the IOExeption on first use of WebRequest

Some .NET Security Patch broke it...
Made PackUrls Public Shared
PackPicker is now Public

So i can get the SelectedIndex from another form.
Populates PackInfo with info of selected modpack.

-Created Public Shared Packinfo
-If Vanilla is not selected then put into PackInfo the split up contens
of the Modpack Text
-If Vanilla is selected then PackInfo is Nothing