Update foaas.coffee

 * adds additional `/:random_fu/:to/:from` options
 * injects to into options, to add `/:to/:from`
 * makes param optional, so fu will fetch `/:random_fu/:from` for
   operations which accept `from` only
If you can change `fu( )?` to `fu ?`, then you don't need to change the `msg.match` index used by `to`. It's also generally better to not capture things you aren't going to use.