Remove root element / root class special cases & validation from glimmer analyzer.

[chriseppstein]

Glimmer no longer requires a root element so it doesn't make sense to automatically put the block's scope on the first element it finds. An explicit block:scope should be used instead.

We should also remove the validation that the "root element" cannot be a class from the block.

[abritinthebay]

We should also remove the validation that the "root element" cannot be a class from the block.

Can you clarify this for me a little more? Guess I need syntax to really get what you mean.