0.9.0: Isolation of CompletionCommand from user-defined global options
To avoid conflicts with application-level options defined by the library user, CompletionCommand
now ignores custom application options. Options from Symfony's base Application
class are retained.
No action is needed to upgrade to this version unless your subclass of CompletionCommand
has been modified to use global options defined by your application. In this case you will need to override CompletionCommand::filterApplicationOptions
to whitelist your options.