fix handling of edges by incremental update

[Eddykasp]

Previously incremental update could run into an issue, where edges were not correctly connected to their target if said target was new. In that case the edge would sometimes be handled before the target resulting in edges connecting to wrong things. This fixes the problem by handling edges only after everything else has been updated.

To reproduce the original issue you can use the below minimal example SCChart and toggle the option induced dataflow: all on and off. The diagram is only drawn correctly after triggering a new synthesis.

scchart ports {
    region R:
    input bool A
    initial state s
    if A go to s
}

[Eddykasp]

👍

[NiklasRentzCAU]

Fixes #160