High level class

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Adds a high level class as suggested by #9 (?)

This is only a first draft, but allows to simply run

HyperDisCo(groupName: "myGroup");

to create a new shared document.

When executing it also prints the code one needs to execute so others can join the same session.

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This misses documentation, but I first wanted to have some feedback before writing docs on it.

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@bgola bump