This change makes QmlApplicationViewer applications find their qml
resources also in non-installed builds, regardless of the current
working directory.

On non-unix platforms applicationDirPath() is not used at all, and on
unix, it's used only for searching applicationDirPath/../path, which
is valid only after install. In-source or shadow-built apps find
their qml resources only if working directory == application
(executable) directory.

Path may refer to subdirectory in application directory. On windows,
non-installed application binary can also reside in /Release or
/Debug, so its resources need to be searched under parent directory
as well.

Change-Id: I81f602406787c20830c656fd5dffd11aa9b4afba
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>