Moving to PHP 5.3+

In the last year things got changed and improved. Lately things are speeding up and part of that we decided to move to PHP 5.3+ because we want to move away from create_function() and start using anonymous functions. For the current patch you can check out https://glotpress.trac.wordpress.org/ticket/305

The current patch will be committed this week and from there we will start looking at other functions that are still calling create_function().