Bug 448778 - Update migration guide for
org.eclipse.e4.ui.workbench.addons.splitteraddon not being API 

Change-Id: I417d10a7f601d57bd70656df88b7cee68403047f
Signed-off-by: Lars Vogel <Lars.Vogel@vogella.com>
Bug 444098 - Update migration guide that the Eclipse context now
contains the Locale directly instead of a String 

Change-Id: I0fab6f84817a16a14c4b6636b890dfff561e392c
Signed-off-by: Lars Vogel <Lars.Vogel@vogella.com>