Changed the way the layout gets hold of the app/top_slot

* kind of passed in on creation, constructor doesn't work maybe
  due to some Java incompatibility
* passing in the Swt App now
refactored ShoesLayout to be clearer
Removed ShoesLayout#contents_alignment and use the slot one

* jay duplication removed
* don't take an argument, it was self all the time either way
* fixes #300
layout --> shoes_layout (naming conventions)
Merge branch 'master' into layoutManager
tiny fix to alphabetical ordering
Removed extra new line, thanks @fism88
Merge pull request #341 from PragTob/layoutManager

Layout manager refactoring