initial idea for how using tags will look

/cc @ianstormtaylor this is working, using the new tags dsl idea

it would get cleaned up / simplified more once we can remove `.load` entirely (after we merge the other 2 prs)
most of the ones don't have names it seems, the ones where it only loads a single tag.

for the ones where there are more than one, i was naming them. but there could also be the case perhaps where you have an integration that:

- loads a single script as their main library
- makes pixel calls using images

bronto does this i think.

so you would have 1 unnamed and 1 named if you wanted, the "main" one and the "pixel":

```js
.tag('<script src="/path.js">')
.tag('pixel', '<img src="/path.gif">'));
```