This adds a simple test of the MarginPen object. Basically to make sure the update to new style object doesn't cause any problems. Can't tell because AngledMarginPen seems to have other internal problems. 
This adds a simple test of the MarginPen object. Basically to make sure the update to new style object doesn't cause any problems. Can't tell because AngledMarginPen seems to have other internal problems. 

git-svn-id: d1efbf6e723fdb101d10d8502afaf9e889ff11cb@569 b5fa9d6c-a76f-4ffd-b3cb-f825fc41095c

fonttools/fonttools,adrientetar/robofab,googlefonts/fonttools