Parse error after enable module (in php 5.2.x)

Technically, the module should have worked in 5.2.5, since that's the minimum requirement for Drupal.

I'll rewrite line 581 so that it works in PHP 5.2. Closures/anonymous functions were introduced first in PHP 5.3.

I have looked into the conflicting line, and sadly it seems that the feature being used (callable functions) was first introduced for SQLite in PHP 5.4. A few attempts at refactoring have failed, so I'll include a note in the readme about this.

Actually, I was able to refactor in a syntax that should work in PHP 5.2.

Attaching patch.