Set colors for 2nd and subsequent remote cursors properly
Set colors for 2nd and subsequent remote cursors properly

Commit 1b784d2 added separation for remote cursors between the internal
"business" model exposed to the EditorStore and the private Swarm model.

The logic to obtain an unused color was not properly accessing the new
internalModel property.

Fixes #19.

ritzyed/ritzy,yakovenkodenis/ritzy,ritzyed/ritzy,yakovenkodenis/ritzy,yakovenkodenis/ritzy,ritzyed/ritzy