QImageReader/Writer: replace dubious use of QSet<QByteArray> with QList

The code populated QSets with some strings and went
on to copy the values to QLists. Since QSet is unordered_set, those
lists were not sorted, so the code did that manually.

Since QSet is a node-based container and not even an ordered one,
the code pays a hefty price just for ensuring uniqueness of values
prior to sorting.

The new code just crams everything into lists, duplicates and all,
then sorts the lists and only then removes duplicates using
std::unique.

Saves 3376B in text size on Linux AMD64 GCC 4.9-trunk release
stripped QtGui.

Change-Id: Ifee931102c01b7505c712cebf4effc37e94165b0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
QFbScreen: fix foreach loops to declare QRect loop variables as const-&

Change-Id: Ieb388b8e1db848bac50ce17488fef04958450689
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
QFbScreen: replace a use of an inefficent QList with QVector

A QPair<QRect,int> is larger than a void*, so better use
a vector to hold them.

Change-Id: I8f0e65836008803b7f619a22ab3a0db1bd493471
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
QVector: add more insert() tests

Add more insert() tests, since the existing ones only covered
the index-based insert() variant and only movable types.

Change-Id: Ifce7a67be0bef45f926f13521873a1d77430e1e3
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
QVector: add removeOne(), removeAll() for QList compatibility

Eases migration from QList to QVector.

[ChangeLog][QtCore][QVector] Added removeOne(), removeAll() for
QList compatibility.

Change-Id: I4211afb2e077c187d0a39f0ac4528f0c66721fb3
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>