Add a basic search typeahead

Summary:
This needs a bunch of refinement but pretty much works. Currently shows only users and applications. Plans:

  - Show actual search results too.
  - Clean up the datasource endpoint so it's less of a mess.
  - Make other typeaheads look more like this one.
  - Improve sorting.
  - Make object names hit the named objects as the first match.

Test Plan: Will attach screenshots.

Reviewers: btrahan, vrana, chad

Reviewed By: vrana

CC: aran

Maniphest Tasks: T1569

Differential Revision: https://secure.phabricator.com/D3110

src/applications/base/PhabricatorApplication.php

@@ -30,15 +30,35 @@ abstract class PhabricatorApplication {
 
 
   public function getName() {
-    return substr(__CLASS__, strlen('PhabricatorApplication'));
+    return substr(get_class($this), strlen('PhabricatorApplication'));
+  }
+
+  public function getShortDescription() {
+    return $this->getName().' Application';
   }
 
   public function isEnabled() {
     return true;
   }
 
+  public function getPHID() {
+    return 'PHID-APPS-'.get_class($this);
+  }
 
-/* -(  Application Information  )-------------------------------------------- */
+  public function getTypeaheadURI() {
+    return $this->getBaseURI();
+  }
+
+  public function getBaseURI() {
+    return null;
+  }
+
+  public function getIconURI() {
+    return PhabricatorUser::getDefaultProfileImageURI();
+  }
+
+
+/* -(  URI Routing  )-------------------------------------------------------- */
 
 
   public function getRoutes() {