Doc: Add missing image to XmlListModel documentation

The image was originally part of QtQuick1 docs - copy it
over to qtdeclarative repository.

Task-number: QTBUG-34556
Change-Id: Ic7089ce157ff7722e5f42b201ff4b01dcff2564e
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Fix a bug in LifetimeInterval:covers()

Change-Id: I7c3b0b2ac43462a9834e3f1891dae23fc9ed061d
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
Better way of handling string additions

The old algorithm still had some quadratic behavior when adding
strings in a loop. This fixes is by keeping track of the longest
substring used, as well as the length of the string. If the length
is larger then twice the length of the longest substring, we
simplify the string.

Change-Id: I9d99ae1632a8046ac135e67bdbb448638d15836d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Handle glyph runs with >65536 glyphs

Done-with: Aaron Kennedy <aaron.kennedy@jollamobile.com>
Change-Id: Ica3a1dccc798186414b92f900b858966ac8dc8c9
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Fix preedit text layout

preeditPosition is relative to the block position

Done-with: Aaron Kennedy <aaron.kennedy@jollamobile.com>
Change-Id: If96a1d0939f84ab11f0642d5fe78d786c30f418a
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>