Commands registered with the command registry will always be handled
first, so as long as we disable any listeners in the registry that were
already invoked for the current command, we don’t need to disable jQuery
methods before replaying the command after activating the package.
This commit adds the ability to call .disableInvokedListeners on the
event passed to the command listeners. This returns a function which
can be called to reenable them.
* Activation events can be handled via atom.commands
* Pre-existing listeners registered via atom.commands are disabled when
replaying events for the activated package.
