Textarea Editable Type

Added a textarea editable type, and updated the Text brick to use it.

STS (steps to test)
* Add a Text brick
* It should have a textarea input for it's "Text" attribute
* Type some text in there, line breaks should be preserved
* Save app
* Refresh
* Value should persist with line breaks intact

Fixes #1905 
Would the input event make more sense here?