Added textarea to allowed inline tags.
Moved attachToForm method from themedui creator to editor core.
Ability to inline editing in textarea added.
Fixing code style.
Fixes to pass all tests.
Fixed variables naming in attachToForm().
Added additional checks if div or textarea are the base for editor.
Reverted ambigious change from editable's bootstrap code.
Fixed code-style in DTD.
Call editor#attachToForm only if editor#element has form.
Various changes to editor#readOnly flag.

* Improved editor#readOnly discovery to consider inline-textarea.
* Changed disabled attribute check from getAttribute to hasAttribute since disabled has no value.
Fixed editor#updateElement doc string.
Re-factored various changes in the inline creator.

* Reverted: Ambigious readOnly fix (now handled by editor itself).
* Reverted: Conditional setData (broken startup event chain by not calling setData event)
* Simplified inline container invokation.
* Fixed initial data set-up (textarea.getValue but nontextarea.getHtml).
* Attach to form only when form is present.
* Improved destroy listener to modify container only when inline-textarea.
Change attachToForm( form, element ) to _attachToForm( form ).
Add comment to _attachToForm.
Add cke_textarea_inline class to created div.
Merge two versions of _attachToForm after rebase.