First draft of template verification RFC

You can certainly use methods in the file resource itself. So you can do:

```ruby
file "/tmp/foo" do
  verify "nginx -t -c #{name}"
end
```

And declare victory. Given that the name attribute for the resource is ```path```, you can also write this:

```ruby
file "/tmp/foo" do
  verify "nginx -t -c #{path}"
end
```

Where this gets strange is when you do this:

```ruby
file "/tmp/foo" do
  verify "nginx -t -c #{path}"
  path "/snoopy"
end
```

At which point you won't get what you expect (which is ```nginx -t -c /snoopy```) - you'll get the earlier value of path. The string interp does avoid this situation. I can channel my inner @sethvargo  and say this is why he would prefer only the block syntax all the time. :)

So: add the new-and-a-little-strange string interp behavior, or accept and document the works-already-in-the-99% case use of ```name```?