OSX startup script bug

Hi,

In IBControllerGatewayStart-OSX.sh:

APP=GATEWAY
...
"${IBC_PATH}/Scripts/DisplayBannerAndLaunch.sh" &

$APP is never exported to the environment of DisplayBannerAndLaunch.sh

Fix is to export $APP:

APP=GATEWAY
export APP

This bug also present in IBControllerStart-OSX.sh