Add Markdow-Textfield component. Solves some of #2

- Send message on enter still works.
- Expanding TextArea via alt + enter works.
- TextArea will shrink back to one row after submit.

Still no edit/delete functionality. This has to be implemented
in the backend first.
Merge branch 'master' into textarea-component
Update md-textfield component with upArrowAction.

Pressing the up arrow inside the md-textfield will send
the upArrowAction when the textfield is empty.
Create DS.Models for channels and messages.
Load messages asynchronously.
Add font-awesome.
Add: Deleting messages works.
Add: Editing messages works.
Merge pull request #3 from LevelbossMike/textarea-component

Add Markdow-Textfield component.