Injecting entitlement to disable the sandbox

[insidegui]

I'm leaving this here if anyone is interested in doing some naughty things with their Marzipan apps such as launching other processes or accessing arbitrary paths on the filesystem. It injects the entitlement com.apple.security.app-sandbox and sets it to false. This behavior is the default, but it can be disabled by setting the environment variable ENABLE_SANDBOX to 1.