Improve YellowBox output format

[janicduplessis]

YellowBox currently assumes the first arg is a printf like format string, this adds support for any arguments so it works more like console in the browser. This also adds stringifySafe to format arguments when using printf style.

The main annoyance that this fixes is when trying to log a single object it will currently print [object Object] instead of the fully stringified version.

Test plan

Tested a bunch of different log combinations.

console.warn({test: 'a'}); // {"test":"a"} (was [object Object] before this patch)
console.warn('test %s %s', 1, {}); // test 1 {}
console.warn('test %s', 1, {}); // test 1 {}
console.warn({}, {}, {}, {}); // {} {} {} {}

[yungsters]

This is great. Thanks (and sorry for the slow turnaround)!

[facebook-github-bot]

@yungsters is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.