Fixed formatting of 0 number literal

[JackieChiles]

I found this issue when using ember-intl. With the following:

Template
{{t 'numItems' num=0}}

Translation
"numItems": "There are ({num}) items"

The rendered string was There are () items whereas the expected output is There are (0) items. This PR allows intl-messageformat to correctly render the literal 0.

[yahoocla]

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[JackieChiles]

@jasonmit This may be of interest to you.

[ericf]

Use {num, number} instead.

[JackieChiles]

@ericf True that will work, but StringFormat handles all other numbers correctly except zero, so I was thinking it makes sense to support it for consistency.

[ericf]

Using number also gives you formatting; e.g. "1,000 items".

I'm going to close this out as it's been brought up before and we decided against it.

[mimecuvalo]

Echoing what I said here: formatjs/formatjs#711
(not sure which project is appropriate)

Seeing that there's many dupes of this and it's for dev's to shoot themselves in the foot here: yahoo/intl-messageformat#88

Would it make sense at least when using a plural rule that it's implicitly treated as a number?