Allow for more than one empty buffer to be open

Closes #679

spec/root-view-spec.coffee

@@ -212,6 +212,11 @@ describe "RootView", ->
           expect(editSession.getPath()).toBeUndefined()
           expect(rootView.getActivePane().focus).toHaveBeenCalled()
 
+        it "can create multiple empty edit sessions as an item on a new pane", ->
+          editSession = rootView.open()
+          editSession = rootView.open()
+          expect(rootView.getActivePane().getItems().length).toBe 2
+
       describe "when called with a path", ->
         it "creates an edit session for the given path as an item on a new pane, and focuses the pane", ->
           editSession = rootView.open('b')

src/root-view.coffee

@@ -173,7 +173,8 @@ class RootView extends View
     initialLine = options.initialLine
     path = project.relativize(path)
     if activePane = @getActivePane()
-      editSession = activePane.itemForUri(path) ? project.open(path, {initialLine})
+      editSession = activePane.itemForUri(path)
+      editSession = project.open(path, {initialLine}) unless path and editSession
       activePane.showItem(editSession)
     else
       editSession = project.open(path, {initialLine})