Added support for an options key that tags on options to all nodes

Hi Matt,

I'm new to chef and ruby but after playing with it and spiceweasel I quickly realized I wanted this feature.  Basically makes it so you can specify global options that get applied to all nodes to cut down on duplication in the yml file.

It would be nice to extend this feature so that you can add options at the cluster level and then have it smartly replace options based on priority global->cluster->node.  This simple change is all I really need for now, though.

I also didn't do any extensive testing other than for my environment but I thought I would share.

Thanks,

Chris