Update Qt to 5.6.2 [1,2]

Thanks to the upstream work of Marie Loise Nolden, we could get rid of a handful
of patches, as they have been properly upstreamed. The rest of the work is just
some minor plist changes.

I would like to thank Loise <nolden@kde.org> for the upstream work, and Adriaan
<groot@kde.org> for getting the update into shape.

[1] http://blog.qt.io/blog/2016/10/12/qt-5-6-2-released/
[2] http://wiki.qt.io/Qt_5.6.2_Change_Files

PR: 213530
Exp-run by: antoine
Submitted by: Adriaan de Groot <groot@kde.org>
Reviewed by: rakuco, mat, tcberner
Approved by: rakuco (mentor)
Differential Revision: https://reviews.freebsd.org/D8228