Improved remote share owner display

The parts of the remote share owner name is now split between user name,
domain name and root so they can be formatted / displayed differently.

The full name is visible in a tooltip.

It doesn't look that good at the moment.
I have split the parts in separate spans so they could be styled differently, for example using different shades of gray.

Please note that a user name can also be "me@example.com@myownclouddomain.com/owncloud" so we need to handle such cases as well.

See screenshot:
![remote-share-owner](https://cloud.githubusercontent.com/assets/277525/3468819/44b3e860-02a4-11e4-901a-f77f9f8c3737.jpg)

TODO:
- [x] discuss / improve how to display the names
- [x] add unit tests

Please have a look @owncloud/designers