API now supports entities/Design changes to "vier"

* The API has been improved so that it now generates entities. This is a feature that isn't supported by statusnet but by the original twitter API. With this, twidere now embeds images. Additionally, links are getting descriptions. There is still work to be done to make it really perfect - but even this state is an improvement, I guess.
* "vier" got some design changes. Now the posts in the network view are separated by a little gap and there are some shadows. I guess its looking better now. Additionally the application name is only shown when hovering over the network name.