[update] update to upstream commit 4615ddd
Squashed 'qtdeclarative/' changes from e4fc75e..811337a

811337a FileDialog.folder property should also be a QUrl, for consistency
87a4a3d QtQml: document QQmlExtensionPlugin::baseUrl
74438ef QtQuick.Dialogs: sync the docs with the implementation
a8e904c Switch to non-streaming version of qWarning()
a73aae2 Undo presumably accidental line deletion
98a0fa0 photosurface: add C++ boilerplate launcher; open button
4e2153a Declarative dialog improvements for the non-Window use case
a4754a3 Update 5.1.0 changelog and what's new
cf01eac QQmlPlatform: rename "mac" to "osx"
55ba0b9 Add missing Q_REVISION
24947fb QColorDialogHelper: Force QWindow before setting flags
d6dc07f Doc: Changed the title to avoid name conflicts and linking errors
9f661cf photosurface demo: behavior depends on initialization order
4455db6 stabilize tst_touchmouse.
e2da7e6 QFileDialogHelper: Force QWindow before setting flags.
278139c move quick dialogs example into an artificial subdirectory again
5ce41d1 Clean up qt quick dialogs example again
f64704f prepare for qt_module_pris.prf changes
5c7f570 Fix compiler warning about unused parameter
b45528f Doc: Exclude Qt Quick Dialogs examples in qtquick.qdocconf file

git-subtree-dir: qtdeclarative
git-subtree-split: 811337a73c160447e5218ae55e93df99ac3d9edd
Merge commit '57a825c55875af675841e4978eb70f438c2dc81c'