Eyetracker-Interface for WebGL-Operate

[p-otto]

This PR adds an EyeEventProvider which connects to the running Eye Tracking Server via a WebSocket and provides the results as Events. Additionally, it refactors the mouseeventprovider, etc. into one plain object in order to have named arguments.

NOTE:
Sadly I cannot reproduce the CI errors locally.

[coveralls]

Coverage decreased (-0.5%) to 17.505% when pulling 7dc5083 on eyetracker into ad7d5f6 on master.

[p-otto]

@MartinBuessemeyer I fixed the CI errors and a copy paste error. The PR looks good for the most part to me. A few things:

1. There are some TODOs in eyegazeevent.ts, are these resolved and if not are they important enough to open issues for them?
2. There are console.log calls in eyegazedatastream. We should remove them or replace them with auxiliary.log if they are important.
3. The websocketAddress in eyegazedatastream.ts is currently hardcoded, this should instead be set by the renderer.
4. The demo should be disabled in demos.json for now, as it is not useful to users without access to an eyetracking setup

[MartinBuessemeyer]

1. I opened one issue in this repo: Add eye tracking track box  #237
2. The console prints are not necessary anymore. Therefore I just removed them.
3. Done.
4. I added an optional argument that is forewarded to the connect method.
5. resovled merge conflicts with master.