Removed two files which are only used by legacy instruments.

There are two files (RequiredIf and RequiredIfGroup.inc), which are written for PHP4 and QuickForm1. They should not be distributed as part of Loris, as they're only used by a couple old instruments (figs and EARLI), Anyone that needs them should include them in their project/libraries directory and be responsible for maintaining them themselves.

In addition, the license is strictly speaking not compatible with the GPL (http://en.wikipedia.org/wiki/PHP_License),