guard against null.data error ref #108

[dcsan]

i made a separate branch just for this tiny fix. you maybe don't want console.warns output but better than errors in the console.

[nickw]

Thanks @dcsan. I actually started using this pattern in other components: https://github.com/meteoric/meteor-ionic/blob/master/components/ionModal/ionModal.js#L66 - perhaps we should stick with that?

[dcsan]

that looks good. coffescript has default args and also the ?= operator...