use strpos instead of substr to detect if we are in the installer
use strpos instead of substr to detect if we are in the installer

jacob-v-dam/forkcms,jessedobbelaere/forkcms,jeroendesloovere/forkcms,Thijzer/forkcms,jonasdekeukelaere/forkcms,bartdc/forkcms,forkcms/forkcms,DegradationOfMankind/forkcms,sumocoders/forkcms,riadvice/forkcms,Katrienvh/forkcms,jonasdekeukelaere/forkcms,justcarakas/forkcms,carakas/forkcms,DegradationOfMankind/forkcms,vytenizs/forkcms,vytenizs/forkcms,mathiashelin/forkcms,sumocoders/forkcms,Katrienvh/forkcms,jonasdekeukelaere/forkcms,jonasdekeukelaere/forkcms,riadvice/forkcms,Katrienvh/forkcms,forkcms/forkcms,DegradationOfMankind/forkcms,tommyvdv/forkcms,sumocoders/forkcms,sumocoders/forkcms,jeroendesloovere/forkcms,Thijzer/forkcms,jeroendesloovere/forkcms,bartdc/forkcms,carakas/forkcms,jessedobbelaere/forkcms,riadvice/forkcms,riadvice/forkcms,tommyvdv/forkcms,carakas/forkcms,jacob-v-dam/forkcms,vytenizs/forkcms,carakas/forkcms,justcarakas/forkcms,jonasdekeukelaere/forkcms,mathiashelin/forkcms,jacob-v-dam/forkcms,sumocoders/forkcms,jeroendesloovere/forkcms,vytsci/forkcms,vytsci/forkcms,mathiashelin/forkcms,Katrienvh/forkcms,jessedobbelaere/forkcms,bartdc/forkcms,forkcms/forkcms,vytsci/forkcms,tommyvdv/forkcms,jessedobbelaere/forkcms,carakas/forkcms,forkcms/forkcms,Thijzer/forkcms,jacob-v-dam/forkcms,tommyvdv/forkcms,DegradationOfMankind/forkcms,justcarakas/forkcms,mathiashelin/forkcms