Fixing createElement wrapper

Raising 'illegal invocation'. Should be called as document method, not
a global function itself
Fixing createEvent wrapper

Same issue as ea0405f657b90af4fedaca8b182eedb4a3eea93f with a "plus":
On older IE's, document.createEventObject, although being a constructor,
exposes the type _object_ disallowing the ```.call``` workaround.

The existent constructor was wrapped as ```document.$$createEvent``` and
called directly.
Fixing type mischeck

Checking for ```boolean``` instead of ```not boolean``` to perform a
_to boolean_ cast, which has no sense. This was raising an
_strict error_ on ECMA5 strict mode compliant browsers.
Fixing wrong constructor location

Trying to build instances of ```ValidityState``` calling the
constructor from ```HTMLElement```. It's located at
```standardize.formElement```
Fixing bad merge strategy

```standardize.merge``` assumes that all objects have prototypes, what
couldn't be true. Now, we prefer prototypes but fallback onto the
objects themselves if the prototype approach fail.
Fixing potential circular reference

The ```CustomEvent``` polyfill try to mimic ```DOMEvent``` prototype
merging itself with the last. But the process of invoke a new
```DOMEvent``` instance, when using ```DOMEvent``` polyfills, mimics our
```CustomEvent``` prototype to exposes methods such ```preventDefault```
and like.

This was already solved, since the ```CustomEvent``` polyfill is, at the
beginning, a ```DOMEvent```.
Assigning hash to standardized document

On the beginning of the function, we check for
```document.standardizeHash```, but this value was never been assigned.
Merge branch 'hotfix/small-fixes' into polyfills
Implementing 'oninvalid' fallback

Older browsers that dont support _oninvalid_ event can complain about
it. We, instead, should trigger an _onerrorupdate_ as a workaround
Fixing add _invalid_ listeners

Mapping _invalid_ listeners to _onerrorupdate_ like described at
41f07101feacddba1e6074e6170dbd2a346dd9bd.
Fixing remove _invalid_ listeners

Mapping _invalid_ listeners to _onerrorupdate_ like described at
41f07101feacddba1e6074e6170dbd2a346dd9bd.
Merge branch 'feature/invalid-event' into polyfills
Implementing event dispatcher polyfill

Some versions uses ```element.fireEvent``` instead of the standard way
```element.dispatchEvent```. We should reroute it here.
Merge branch 'feature/event-dispatcher' into polyfills
Refactoring

Small refactor to strip one line