Added initial file system support for winrt

While some functionality is not available for winphone
(QFileSystemEngine::tempPath), some functionality can
be fully supported. Other cases like checking for stale
processes which is needed by QLockFile cannot be covered
that easily as obtaining information about other processes
is limited due to sandboxing.

Change-Id: I9ea80ae2b421eea1ddfd4c5bc2f4b6f8adaee85f
Done-with: Kamil Trzcinski
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@digia.com>
WinRT QPA: Fix touch release on phone

The IsInContact API is not reliable on phone, so use IsLeftButtonPressed
instead.

Change-Id: If17089f976586879355f127dadbe394b57afe3c3
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@digia.com>
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>