…ted mode

* Reasoning: It is difficult to judge, what is the most often used combination of settings and thus, which should be the default settings for the grapher. For the case of analysing single tracks the item source "track of selection" makes most sense. Also in this case drawing the edges in the grapher between these points makes sense. In other cases, such when inspecting large selections or even the dataset as a whole, showing the edges does not really help and leads to a very confusing plot. For the case of inspecting the full dataset without any selection the setting "track of selection", leads to an empty plot, when the grapher is first show. Thus, with this commit, the defaults are changed to full graph context and non-connected.

… graph changed was called

* Reasoning: before, there was fixed timeout. However, with large datasets, it could have happened that graphchanged() + layout() was not completey performed before zoom out was started leading to unexpected behaviour. This commit introduces a process that lets the zooming out wait until the graph was layouted once according to the current data.