material-textarea

[andryfailli]

Hi,
This is my first contribution, a simple implementation of material-textarea.
There is a lot of code duplicated from material-input, maybe you have some idea to refactor.

We can also consider implementing an "auto-grow" feature. (I've tried https://github.com/monospaced/angular-elastic and it works like a charm)

[marcysutton]

If we are to add a textarea component it will need a few things for accessibility:

1. The textbox role
2. It needs aria-multiline="true" to be a multiline component
3. If it is disabled, aria-disabled="true"
4. Keyboard events to submit depending on whether it is multiline

More information: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/ARIA_Techniques/Using_the_textbox_role

Here is the relevant section of the Material Design spec: https://www.google.com/design/spec/components/text-fields.html#text-fields-multi-line-text-field

[marcysutton]

Duplicate of #534.