Validate qmlEngine() in QDeclarativeItem::mapToItem() function.

We protect against the fact that engineForScript() can be
called with 0 or something else.

Task-number: QTBUG-29572
Change-Id: I92f62b328d1e84a378449e0857569886f327077c
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Add missing argument to QBasicUnixFontDatabase::fallbacksForFamily()

Change-Id: I403745b8c734092078011b56fa0373981d9ad119
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
QNetworkProxyFactory: check all the proxy environment variables

QNetworkProxyFactory used to check only for the http_proxy environment
variable in systemProxyForQuery. This patch makes it look as well in
https_proxy, ftp_proxy and all_proxy. http_proxy is still used as a
fallback value.

Change-Id: I7934af70d191cd17dbce3b3789260ae1a8332986
(cherry-picked from qtbase commit a7d1b6419d7503474ed5e02f7fb984e4ad5f9219)
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>