This change moves 'Extending QML' qdoc file and the tutorials
from examples/quick to examples/qml, which is the correct
location for them.

Change-Id: I24bd9dfa75baaab7bc8efe08489f09a7b65d98a6
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>
Reviewed-by: Alan Alpert <aalpert@blackberry.com>

Some examples were duplicated a few times. Removing the excess.

Change-Id: I6fa59f79de63ac952103421ba1c063f5912b702b
Reviewed-by: Martin Jones <martin.jones@nokia.com>

Symbols beginning with QDeclarative are already exported
by the quick1 module.

Users can apply the bin/rename-qtdeclarative-symbols.sh
script to modify client code using the previous names of the
renamed symbols.

Task-number: QTBUG-23737
Change-Id: Ifaa482663767634931e8711a8e9bf6e404859e66
Reviewed-by: Martin Jones <martin.jones@nokia.com>