Add javelin_tag(), convert easy callsites

Summary:
  - Implements `javelin_tag()`, which is `javelin_render_tag()` on top of `phutil_tag()` instead of `phutil_render_tag()`.
  - Manually converts all or almost all of the trivial callsites.

Test Plan:
  - Site does not seem any more broken than before.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D4639

src/infrastructure/diff/PhabricatorInlineCommentController.php

@@ -234,14 +234,14 @@ abstract class PhabricatorInlineCommentController
   }
 
   private function renderTextArea($text) {
-    return javelin_render_tag(
+    return javelin_tag(
       'textarea',
       array(
         'class' => 'differential-inline-comment-edit-textarea',
         'sigil' => 'differential-inline-comment-edit-textarea',
         'name' => 'text',
       ),
-      phutil_escape_html($text));
+      $text);
   }
 
 }