Allow silent failure

[alundr]

Allow silent failure.  This would be a great help in drawings when dimensions fail to find the needed edges

example

Child LinearDimension_1 As :IvLinearDimension

    part1 = viewModel
    part2 = viewModel

    entity1 = "Edge1"

    entity2 = "Edge2"

    silentFail = True

End Child

I would rather the program fail to apply a dimension and complete then the entire program come to a screeching halt and end up with nothing.