Move TabFolderLayout into SWT and set it as a default in TabFolder

[laeubi]

Today I debugged some issues with TabFolder and noticed that it at least behaves strange if tabs are added dynamically, after investigate a little bit more I tried to fix it with an own Layout as usual layout mangers (like FillLayout) get sometimes confused as TabFolder has more childs than are actually displayed.

Short after that I noticed that there are already some instances of TabFolderLayout in platform:

They all seem to be copies of each other (more or less) except the license header and when they where added, I therefore wonder if we should simply add that layout to SWT and even set it by default to TabFolder.