Enhance file transfer styles

File transfer styles have been enhanced.

![progress](https://f.cloud.github.com/assets/41547/992389/4ce2f9de-097d-11e3-8268-3ad3c7396ae8.png)

Also, I've extracted the verbose template code to a `<script type="text/template">` tag within the `chat.html` file.

I didn't feel specific tests were needed for this, though as I'm just back from holidays, I'm possibly too lazy and wrong :)