Changed 'complete' option default to "sfl", meaning we have awesomebar completions by default now.

In constrast removed history cache, which should make startup faster and use less memory. As we only need it for :history anyway, there is no real performance penalty as Places does search quite fast.

content/events.js

@@ -517,10 +517,6 @@ function Events() //{{{
             let url = doc.location.href;
             let title = doc.title;
 
-            // update history
-            if (url && liberator.has("history"))
-                history.add(url, title);
-
             // mark the buffer as loaded, we can't use buffer.loaded
             // since that always refers to the current buffer, while doc can be
             // any buffer, even in a background tab