Update README

For documentation of this version see [here](https://github.com/AKSW/semann/wiki/Documentation).
Used libraries are listed [here](https://github.com/AKSW/semann/wiki/Libraries-Used)

**Features**
* Adding and fetching annotations to and from the local Virtuoso backend
* Finding similar publications based on annotations in the currently open file

![screenshot](https://cloud.githubusercontent.com/assets/5968369/2620353/de60e07a-bc3c-11e3-8a5e-c4ee1c33738e.png)