Allow autocomplete package to be deactivated

src/packages/autocomplete/lib/autocomplete.coffee

@@ -2,8 +2,15 @@ AutocompleteView = require './autocomplete-view'
 
 module.exports =
   autoCompleteViews: []
+  editorSubscription: null
 
   activate: ->
-    rootView.eachEditor (editor) =>
+    @editorSubscription = rootView.eachEditor (editor) =>
       if editor.attached and not editor.mini
         @autoCompleteViews.push new AutocompleteView(editor)
+
+  deactivate: ->
+    @editorSubscription?.off()
+    @editorSubscription = null
+    @autoCompleteViews.forEach (autoCompleteView) -> autoCompleteView.remove()
+    @autoCompleteViews = []

src/packages/autocomplete/spec/autocomplete-spec.coffee

@@ -33,6 +33,17 @@ describe "Autocomplete", ->
       rightEditor.trigger 'autocomplete:attach'
       expect(rightEditor.find('.autocomplete')).toExist()
 
+  describe "@deactivate()", ->
+    it "removes all autocomplete views and doesn't create new ones when new editors are opened", ->
+      atom.activatePackage('autocomplete')
+      rootView.getActiveView().trigger "autocomplete:attach"
+      expect(rootView.getActiveView().find('.autocomplete')).toExist()
+      atom.deactivatePackage('autocomplete')
+      expect(rootView.getActiveView().find('.autocomplete')).not.toExist()
+      rootView.getActiveView().splitRight()
+      rootView.getActiveView().trigger "autocomplete:attach"
+      expect(rootView.getActiveView().find('.autocomplete')).not.toExist()
+
 describe "AutocompleteView", ->
   autocomplete = null
   editor = null