[BUGFIX] Fixed implementation of preProcess() hook in 6.0

This update fixes the following issue:
https://github.com/NamelessCoder/flux/issues/19

See code comment in ext_localconf.php for more.
Merge pull request #21 from murderfacemurderfacemurderface/Issue_19

[BUGFIX] Fixed implementation of preProcess() hook in 6.0