Fix for url bug in the qmlvideo examples.

In the FileBrowser paths where being prepended with file:///, since all
the paths already starts with a forward slash, navigating away from the
initial directory was therefore not possible.

To make the examples work on Android, QT += multimedia was added.

Change-Id: Iff96729d476c4292999b022bdd6d5770b6b011e7
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>
Android: Fix for uncaught java exception.

If an exception's getMessage() function returns a null object, we can't
send it directly to the Log function, as it will throw an exception...
To avoid this we can prepend the string from getMessage() with an empty
string.

Change-Id: Ie026cbf9af133352919a4536c152b6d35cb8c0a7
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I0361cbb4f5398bb13e675c3de04519c414daea43