Calling increment/decrement with tags, callback and no value

[aheuermann]

I noticed that the following call results in an invalid metric format.

hotShots.increment('some.metric', { tagName: 'tags' }, callback);

I think the issue is due to the arguments length check here.

[bdeitte]

Yep the way that increment and other functions deal with missing args is... unusual. But it's been this way for a long time and is a bit tough to consider changing for legacy reasons. If someone sees ways we can make this better that looks safe, and tests cover it, I'm good with it.