[Qt4-preview-feedback] Assistant navigation regression

[philwave at gmail.com]

In previous version (4.4x) of Qt, you used standard keys for the Back and  
Forward Assistant functions.
Under Windows, this i: Alt+Left and Alt+Right.
And as a matter of fact, these are standard keys according to the Qt  
Reference (cf.
QKeySequence). And indeed, PC keyboards that have extended keys use
these shortcuts (eg. my Microsoft Keyboad).
Therefore it was really good AND standard in Qt 4.4.
You even use these shortcuts for the Browser Demo Application.

BUT in Qt 4.5 Assistant, you have changed for new non-standard shortcuts!
This breaks the compatibility. I consider this as a regression
and suggest to come to the earlier situation.

Moreover, in Qt 4.4, you added code to handle XButton1 and XButton2  
releases
to go backward and forward, respectively (which is standard to browse with  
the mouse buttons).
This does not work anymore in Qt 4.5 :-(