Unable to add new files unless logged in as Admin

Steps to reproduce:

1. Give a role the 'Add new files to themes' permission
2. As a user with that role, go to the theme editor

Expected behavior is that User sees 'Add a New File' drop-down box. Observed: no 'Add a New File' drop-down

The cause is most easily identifiable with the following command:

claar:/tmp/theme_editor-HEAD$ grep -ion '.*add new files to themes..' *
theme_editor.inc:77:    $newfile=(!user_access('Add New Files to themes')
theme_editor.module:40: $perm[] = 'Add new files to themes';
theme_editor.module:60:    'access arguments' => array('Add new files to themes')

On line 77 of theme_editor.inc, "New" and "Files" begin with uppercase letters, which doesn't match how the permission is defined in theme_editor.module. The attached patch against HEAD fixes this.