Add more key names to QKeySequence.

So that, for example,

qDebug() << QKeySequence(Qt::Key_Cancel).toString();

prints "Cancel" instead of "ᡀ".

Task-number: QTBUG-953

Change-Id: Ib17fc314fd018355e6a1826d26fce85fdcbbe0c8
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Implement support for global whatsthis on Windows

Task-Number: QTBUG-32835

Change-Id: Ifee10d815ce0037c96eda574ab9e1af67ff6bd78
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
qdoc: Clarify documentation of member functions

When implementing a custom subclass of QAbstractItemModel,
if the custom model will use MIME types other than the
default internal MIME type, the mimeTypes() member must be
reimplemented to return the list of allowed MIME types. If
mimeTypes() is reimplemented, mimeData(), canDropMimeData(),
and dropMimeData() must also be reimplemented to use the
allowed MIME types.

Task-number: QTBUG-32362
Change-Id: Iee5cf5d2dbed8a6c1f7ab47a7a4b9b03e80e8e59
Reviewed-by: Venugopal Shivashankar <venugopal.shivashankar@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>