False positive on comment changes

[sylvestre]

checkiid is triggering an error on comment changes. For example, on this changeset:
http://hg.mozilla.org/mozilla-central/rev/feded4c79308

Maybe it should ignore line starting with:
^+[:space:]*

[jwir3]

Maybe it should ignore line starting with:
^+[:space:]*

I can implement this fix, but the comment handling is a little more complex, because we should be able to handle block comments smoothly. This doesn't seem like a big issue, but the block comment can be large enough that it isn't actually in the patch (hence the reason we need to look at the actual file in some cases). I believe this is being tracked by issue #1.