Properly submit the right HTTP method type to rails

So, in some scenarios, Rails will embed the expected action for the route inside the form itself, as a `<input type="hidden" name="_method" value="PATCH">`

Our serializer serializes that, and Rails is happy.

The mistake was in assuming that Rails always places this `_method` input there.  In at least the following scenarios, it does not:

- GET
- POST
- PUT (the surprising one)

This results in cases where your endpoint only responds to `PUT` and we're doing a `POST` with `tg-remote` forms => 404.  I believe this also causes `method="GET"` forms to do a POST atm

I'm betting it's because of browser limitations that it doesn't actually use the native HTTP method type.

Solution:  Use `method` attribute on `form`, and serialize it into the mix *if there is no `_method` there already*

This PR adds example forms of each type + tests for each.  

This PR also adds an attribute:

- `tg-remote-norefresh` no value, presence on the initiator will make sure that no `Page.refresh` will occur

cc @celsodantas @tylermercier @nsimmons @kurtfunai @patrickdonovan  
Yes. But I don't think Rails keeps `PUT` in the form method.

from Shopify's production code:
![screen shot 2014-12-12 at 12 11 48 pm](https://cloud.githubusercontent.com/assets/408219/5415869/73b8d6f6-81f8-11e4-99c4-c45d13c49ab7.jpg)

And from Rails guides:
![screen shot 2014-12-12 at 12 07 46 pm](https://cloud.githubusercontent.com/assets/408219/5415888/9d891ffe-81f8-11e4-945e-3fafca004d8b.png)

If it's not doing it in some places, I assume it's a bug in Rails. =/