Auto-scroll while selecting entire rows/columns did not work

If you press and hold a section in a header view you can extend the
selection to more rows by moving the mouse. This worked fine until you
moved the mouse outside the geometry of the header view. The expected
behavior was then to scroll the view (this is what happens with extended
selections on regular table cells).

[ChangeLog][QtWidgets][QHeaderView] Auto-scroll the view when making
extended row/column selections.

Change-Id: Ic65aa34d370e74054b2123ab57edb1add0e8adb9
Task-number: QTBUG-21201
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>
(cherry picked from qtbase/f9408317e70bc2e635a2f9baeff35d1c06227734)
Bump Qt version to 4.8.7

Change-Id: Icd6fcdb59eb1b9fd8de555ef1c1c87a379f06a27
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Rewrite debug output of event classes.

Bring debug formatting in Qt 4 on par with Qt 5.4:
- Introduce functions to return class name and type name by type.
- Add verbose output for DnD, tablet, native gestures and context
  menu, events.

Task-number: QTBUG-38858
Task-number: QTBUG-42344

[ChangeLog][QtGui][QEvent] The debug output for events has
been significantly improved.

Change-Id: I3f11e34c3c9d6a3c6db596be4051b801f00e6153
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
(cherry picked from qtbase/14f9c09542bd6cc19430473da9ce4c68f239ec7d)
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>