Add QLocale::toUpper/Lower

Add QLocale::toUpper/Lower

The toUpper/Lower() methods in QString should not
be locale dependent, as this can lead to rather
hard to find bugs in at least a turkish locale.

Rather have explicit, locale dependend case conversions
available in QLocale.

Reviewed-by: Denis Dzyubenko
(cherry picked from commit da0e1e101bb4c44c25b6523357fa81ad1b2d6539)

Change-Id: I1cc3f341bef17ad573a736dc94c9c5d514ace54e
Reviewed-on: http://codereview.qt.nokia.com/3259
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>