Various independant behaviours added ontop of webviews. 

These build ontop of Webkit.WebView, the Services modules, and/or possibly WebTab
to add various useful behaviours. They all (with the exception of
navigate/view-source) run some code (through the init.vala module) for every
new WebView and/or WebContext and are not called into in any other way.

They are essentially plugins with a very limitted but capable API to build on. 

## Groupings

These traits are organized by how the extend the webview or other UIs:

<dl>
  <dt>autocomplete</dt>
  <dd>These extend the Completer service rather than a WebView.</dd>
  <dt>navigate</dt>
  <dd>These handle page loads via a range of signals on the WebView.</dd>
  <dd>These may include custom protocols, decide_policy, load_failed, & load_changed.</dd>
  <dt>decorate</dt>
  <dd>These respond to other signals on the webview and may trigger changes to the WebTab.</dd>
</dl>
