The Eclipse Plugin was discontinued by the Eclipse Vorto project. This is a friendly fork from the Vorto Repository and not officially related to Eclipse Vorto.
Clone the offical Vorto Repository and install the bundles:
git clone https://github.com/eclipse/vorto.git
cd vorto
mvn clean install
cd ..
Clone this repository:
git clone https://github.com/Ebolon/vorto-eclipse-plugin.git
cd vorto-eclipse-plugin
Now you can build the Vorto Eclipse Plugin
mvn install