Handle errors thrown by Intl formatters

[stasm]

In cc32a1e we started catching errors thrown by Intl formatters inside of FluentType. Should we report them somehow?

[brettz9]

While you're at it (and I'm new to this, so just wrapping my head around your API now), would it not be useful to have a way of passing in options to the Intl formatters from the JavaScript API as opposed to only within the messages?

[zbraniecki]

@brettz9 please, take a look at the Fluent tutorial, section on Partial Arguments - http://projectfluent.org/fluent/guide/functions.html#partial-arguments

[stasm]

Fixed in #398 on the release branch.