Fix: Fix behavior of ignoring comments within previous nodes (refs #256)

[kaicataldo]

While adding tests to the main ESLint repo to account for the changes I made in #257 I realized that some of my initial assumptions were wrong:

• That the body prop is always an array (in reality it can be an array or an object)
• I didn't check the body props recursively (I had incorrectly thought the Program node's body contained all the nodes, which, in retrospect, is pretty silly)

This means that my current merged fix does not account for this case, as the comment to remove is nested a few levels deep, with the body props being a mixture of arrays and objects as you drill down:

function a() {
    var b = {
        // comment
    };
    return b;
}

I'm going to test out the main ESLint repo with this branch now, but wanted to see if I could get some eyes on this to see if it made sense. Thanks!

[kaicataldo]

Tested by npm linking it to the main eslint repo. Was able to remove this guard (which is what alerted me to this problem in the first place!) and all the tests pass.

[nzakas]

Lgtm