Support visual cursor movement of bidirectional text in TextInput and TextEdit

This was observed with Qt 4.7 from git://gitorious.org/qt/qt.git
with HEAD at d63778ce3942130eb6fdd8ef173ba50ed0f49a5c

Run the code below:

import QtQuick 1.1

Rectangle {
    width: 800
    height: 640
    color: "#404040"

    TextInput {
        text: "Some bidi sample text عينة من النص Lorem ipsum dolor عينة من النص"
        anchors.centerIn: parent
        font.pixelSize: 20
        focus: true
        selectByMouse: true
        width: implicitWidth+10
        Rectangle { color: "white"; anchors.fill: parent; z: -1 }
    }
}

1) Pressing the left/right arrow key, the cursor should move left/right across all the text. Instead it changes direction when moving from English to Arabic and vise versa.
2) Although the selection of text generally work as expected, dragging a selection by mouse from the left end of the text to the very right end leaves the last section of Arabic unselected.
3) Place the cursor at the center of an Arabic word and enter some English characters. The characters appear at the right place, but the cursor is not drawn at the right of the last character typed.