allow functions.php to be included many times
allow functions.php to be included many times

apparently laravel workbench requires this
fixes #636
see #649

Sgoettschkes/assetic,matthiasmullie/assetic,lenar/assetic,renaatdemuynck/assetic,mubassirhayat/assetic,matthiasmullie/assetic,lenar/assetic,shandy05/assetic,renaatdemuynck/assetic,mubassirhayat/assetic,mubassirhayat/assetic,lenar/assetic,matthiasmullie/assetic,lellimecnar/assetic,lellimecnar/assetic,shandy05/assetic,shandy05/assetic,shandy05/assetic,Sgoettschkes/assetic,renaatdemuynck/assetic,kriswallsmith/assetic,Sgoettschkes/assetic,kriswallsmith/assetic,lenar/assetic,renaatdemuynck/assetic,lellimecnar/assetic,Sgoettschkes/assetic,kriswallsmith/assetic,matthiasmullie/assetic,lellimecnar/assetic,kriswallsmith/assetic