Stop using anonymous functions, they don't work in PHP 5.2

git-svn-id: http://plugins.svn.wordpress.org/jetpack/trunk@758380 b8457f37-d9ea-0310-8a92-e5e31aec5664
Jetpack: Widget Visibility: Including option to filter based on if something is on the front page. Back-end was already there, just needed the option.

git-svn-id: http://plugins.svn.wordpress.org/jetpack/trunk@758473 b8457f37-d9ea-0310-8a92-e5e31aec5664
Jetpack: When calling Jetpack::get_content_width() if the global content_width isn't set, pass a zero to the filter instead.  Themes really should be setting this on their own, however.  Fixes #1878

git-svn-id: http://plugins.svn.wordpress.org/jetpack/trunk@758489 b8457f37-d9ea-0310-8a92-e5e31aec5664
Jetpack: Widget Visibility: Let translators decide what  is.

git-svn-id: http://plugins.svn.wordpress.org/jetpack/trunk@758493 b8457f37-d9ea-0310-8a92-e5e31aec5664