Update timber-core.php
Update timber-core.php

fix for off chance that $key is empty (had issues with ACF)
josephbergdoll/timber,Jmayhak/timber,aaemnnosttv/timber,anugupta/timber,josephbergdoll/timber,gchtr/timber,pensesmart/timber,jarednova/timber,aprendiendoando/timber,gbarberi/timber,josephbergdoll/timber,mgmartel/timber,ogrosko/timber,joelgarciajr84/timber,lucasmichot/timber,PrisisForks/timber,mgmartel/timber,xavierpriour/timber,jnweaver/timber,pensesmart/timber,xavierpriour/timber,xavivars/timber,ogrosko/timber,rpkoller/timber,rpkoller/timber,anugupta/timber,xavierpriour/timber,mgmartel/timber,jnweaver/timber,Jmayhak/timber,PrisisForks/timber,lucasmichot/timber,gbarberi/timber,gchtr/timber,blocher/timber,gchtr/timber,joelgarciajr84/timber,jnweaver/timber,aprendiendoando/timber,pensesmart/timber,aaemnnosttv/timber,aaemnnosttv/timber,anugupta/timber,jarednova/timber,joelgarciajr84/timber,ogrosko/timber,gbarberi/timber,mojaray2k/timber,lucasmichot/timber,timber/timber,mojaray2k/timber,blocher/timber,mojaray2k/timber,timber/timber,xavivars/timber,Jmayhak/timber,rpkoller/timber,xavivars/timber,jarednova/timber,PrisisForks/timber,aprendiendoando/timber,blocher/timber