shoes/shoes4 — pull request #627 by KCErb (2014-04-03 23:15:53+00:00)
Title: Margin= method

Partially addresses #622. There's probably a prettier way to do this . . .

You may notice that in the following app:
```ruby
Shoes.app do
f1 = flow do
background lightblue
para "This is a flow"
end
button "click" do
f1.margin = [10,10,10,10]
end

f2 = flow do
background lightblue
para "This is another flow"
end
button "click" do
f2.margin = 10
end
end
```
The background doesn't adjust to match the new margins. I think this has something to do with #617 or #618, so I'll play with this for a separate PR.