Android: Use a file descriptor for all local media files.

Using a fd is more consistent across different Android versions and
also works with files that are in the applications private storage.

Task-number: QTBUG-39346
Change-Id: I462822459d12d7842d15f1cb7caafc75c18fe32c
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
Fix static initialization order fiasco in some plugins.

Some static variables were initialized using QMediaMetaData
values, which are also statically initialized.

Task-number: QTBUG-39202
Change-Id: Ibedc0a77d96cdfa575aad122c4ec654e6830e1f7
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>
Make multimedia QML types available for the 5.3 import version.

At least one type needs to be registered with the 5.3 version number to
make it known to the QML engine.

Change-Id: Iacfe62650b4194fbb89135fef7cb148309227ce2
Reviewed-by: Alan Alpert (Personal) <416365416c@gmail.com>
Merge remote-tracking branch 'origin/stable' into 5.3

Change-Id: I689554fb6e47b8183013de271a776909a05398dc