Add statuses create and fetch in the examples

[azizhk]

I did not know whether this was status or statuses and could not find any reference to it. Then found statuses here: https://github.com/philschatz/octokat.js/blob/8e9312ea669c840fde16a1aa022c8658f4158c56/src/grammar/tree-options.js#L62

So thought I should add it here making it easier for others to find it.