Fix visual bugs in FlowHideLayout/FlowWrapLayout #169

While implementing it, I noticed that in some cases some components will overflow the parent container.

This could be a bug in the component or in the layout manager. I assume that the cause is that it sums the minWidth of each component and doesn't account for the padding introduced by the MigLayout?

It might be something else, there are many things at play here. This is a low-priority issue, given that it is relatively rare to occur and the code is a pain to work with.