[518986] Title of compare editor should be computed in the background

- Use dedicated background job with short to compute the compare editor
title instead of blocking the UI thread
- Slightly tweak title computation

Bug: 518986
Change-Id: I181a3980b03c92b2441bb12bedae24367644d877
Signed-off-by: Martin Fleck <mfleck@eclipsesource.com>
1 file changed