Allow OTFs to call standard Foundry chat commands.

[mjeffw]

Here's an example from one of our users:

/if [M:"Halberd (Swung)"] s:{/r [D:"Halberd (Swung)"]} cs:{/m CritHitCalcMelee attack="Halberd (Swung)" kbm=1 fon=none } f:{/ic I missed!} cf:{/fp -1 \\/ooc:You crit failed your attack, so you drop your weapon!}

Notice that the critical success clause is using the standard Foundry /macro chat message, while the two failure cases are using /ic and /ooc.