Make animations set their initial values immediately

Summary:
Currently, it takes one frame for animations to set their first value. For fading stuff in, that means it briefly appears at 100% opacity, then jumps to 0%, then fades in from there.

Instead, immediately tween to the initial value.

Test Plan: Comments in Pholio fade in nicely. Preview is still a janky pile of mess until D6267.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D6268

src/__celerity_resource_map__.php

@@ -2442,7 +2442,7 @@ celerity_register_resource_map(array(
   ),
   'javelin-fx' =>
   array(
-    'uri' => '/res/c7cefec3/rsrc/externals/javelin/ext/fx/FX.js',
+    'uri' => '/res/23fb3d44/rsrc/externals/javelin/ext/fx/FX.js',
     'type' => 'js',
     'requires' =>
     array(

webroot/rsrc/externals/javelin/ext/fx/FX.js

@@ -87,6 +87,9 @@ JX.install('FX', {
       this._interval = setInterval(
         JX.bind(this, this._tween),
         Math.round(1000 / this.getFps()));
+
+      // Immediately update to the initial values.
+      this._tween();
     },
 
     _tween: function() {