Add blur validation to free trial form

**Change 1**:
The old PPC landing page validating the required fields on blur in addition to submit. This adds the validation for each required input on the blur event as well as the submit event to the new form.

To test, load the /free-trial page. Then focus into the `url-input`, `name`, and `email` fields. For `url-input` and `name` enter nothing and then trigger the blur event. For `email`, enter an invalid email. If all fields are invalid after blur you should see this:

![screen shot 2014-12-09 at 3 58 36 pm](https://cloud.githubusercontent.com/assets/150579/5365752/78eeb476-7fbc-11e4-9aff-62cbdececa44.png)

**Change 2**:

Whenever a validation error happens, an event should go out that looks like this:

category: forms
action: seo-form email error blur/seo-form email error submit
label: true/false
value: [character length of the input's value]

**Change 3**:

The input focus events are now unique. They will only fire on the first focus event on the input.

**Change 4**:

An additional event has been added to track successful submissions that followed a validation error. This is intended to help us track how many people submit the form with an error, go back and fix it, and then successfully submit. This event has the following anatomy:

category: form
action: seo-form success after error true/seo-form success after error false
@kylerush not sure if jQuery 1.6 supports it but you can add a `once` event listener on `focus` then you wouldn't have to add the `focus-tracked` class