Added KeyboardEventTarget

* Removed filtering on textarea and input types
* Added new KeyboardEventTarget class with target element
Fixed minor issues per discussion

* Added period at end of class definition
* Modifed properties to be get only
* Updated invalid description on property

Reference: #116
changed wording on get properties to 'gets the...'
Merge pull request #117 from Buildstarted/master

Added KeyboardEventTarget