Ruby 1.8.x compatibility fix and support for templates in different cookbooks

I had tweak a few things to make this cookbook work in our env (ubuntu 12.04 hosts):

* `default.rb` has Ruby 1.9 hash syntax in it, changed to 1.8 syntax
* Added support for `template_cookbook` and `template_syntax` to allow sourcing the template from a different cookbook (that we don't necessarily control)
* A small tweak to use the file resource's `delete` action instead of shelling out to `rm` directly.