GraphalyzerProBugFix#2(US#64)

Implemented GapToMarginConverter, SequenceDiagram, DiagnoseOutputViewModel, IDiagnoseOutputViewModel, ProcessViewModel, ThreadViewModel.

All mother processes are at least as long as the included child processes.
Merge pull request #55 from GraphalyzerPro/GraphalyzerProBugFix#2(US#64)

GraphalyzerProBugFix#2(US#64)