Update Ember.TextArea and Ember.TextField documentation

text_area.js:
 * update @extends documentation from ```Ember.View``` to ```Ember.Component```
 * reference ```handlebars.helpers.textarea````

text_field.js:
 * update @extends documentation from ```Ember.View``` to ```Ember.Component```
 * reference ```handlebars.helpers.input````

controls.js
 * add note for Ember.TextArea and Ember.TextField extending from Ember.Component
 * add references to Ember.Component; warning about not inheriting parent view controller