Add icons to switch between side-by-side and unified diff view

For change edits the icon is not displayed, because the unified diff
view is not able to handle change edits yet.

Change-Id: I02b9800d40a510b9f90d6890e619aec89c8933d5
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
10 files changed