au Add "use" to namespace declaration

This used to add a (:use ) clause to the namespace declaration, but now it adds a (:require ) along with :refer. Then it gives you several tabstops to help you write your require statement:

• 1st tabstop lets you type out the namespace, the example in [example :refer [foo]]
• 2nd tabstop wraps the brackets in [foo], letting you type out :all if you want.
• 3rd tabstop is inside the brackets (just foo), where you list the vars you require.

Once you're through the tabstops, the cursor jumps back to where you were. If cljr-auto-clean-ns is true (the default), the namespace is cleaned up afterwards. Likewise for cljr-auto-sort-ns, which sorts it.