Refine tool menu behavior
Refine tool menu behavior

Since the tools menu has been turned into a dropdown:

* Open the menu before showing the preview and exit tour guiders.
* Use the slideToggle() jQuery effect instead of toggle() to show
  and hide the menu.
* Show the tooltips to the left of the menu items.
* Close the menu when the "Preview" item is clicked.

Addresses #579

denverfoundation/storybase,denverfoundation/storybase,denverfoundation/storybase,denverfoundation/storybase