I did this together with Christiaan Janssen

Reviewed by: Christiaan Janssen

When changing the language, the sidebar items would break because
their localized window titles were used for storing the settings. Now,
id's are used.

Reviewed-by: con

Reviewed-by: hjk

Reviewed-by: kkoehne

Reviewed-by: Marco Bubke

Task-number: QTCREATORBUG-1292

Expressions are now shown as a tooltip if an expression is set

See: BAUHAUS-648

Discussed-with: hjk

Do it in the destructor instead.

Reviewed-by: hjk

Reviewed-by: Jens Bache-Wiig

Reviewed by: Kai Koehne

* Make sure we only change our own urls inside that function
* QDesktopService::setUrlHandler expects the target slot to take a QUrl

Reviewed-by: ck

Reviewed-by: ck

The Navigator and the Property Editor now show the same error
message for invalid nodes

See: BAUHAUS-611

* Fixed an issue with text eliding on combo boxes
* Fixed placement of arrow on elided comboboxes

Task-number: QTCREATORBUG-1278

Task-number: QTCREATORBUG-1288