Revert "Make unicode ranges in font take precedence over codepage"

This reverts commit 3a84d92f5736da3dc3f6a385bf3723984a5640ed
because it caused a regression with certain fonts on Windows that
have divided information about writing system support in unicode
ranges and codepage ranges.

The original commit fixed a problem on Android where one
of the fonts had an entry for Arabic in its codepage range but
no glyphs for this script. This issue has been fixed in a different
way now, by 0b87f4f6c912a508f170cd25ff5317bb77665fa9 which makes
fallback fonts work properly, so the commit is no longer needed
to fix said bug.

[ChangeLog][Fonts] Fixed regression in font families returned by
QFontDatabase::families() for certain writing systems.

Task-number: QTBUG-39846
Change-Id: I3077b1e618b21680549abc1734cb6df6e264387e
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
QGLXContext survives screen removal

The screen pointer is usually only used to get the Display, which normally
doesn't change anyway.

Task-number: QTBUG-39996
Change-Id: Ie35f02fc9330647897a9f081afb8c9ce550eed2a
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Android: Fix crash at shutdown when keyboard is visible

This is a follow-up to 4c6ebe5f9e4ddc0d799a0f2bf4aef9f7e48e0dfb.
Crash was still 100% reproducible for me with the previous fix.

Task-number: QTBUG-40957
Change-Id: Ie59cfe4f1fc746251fe06ba96369738098b2a35f
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>
QCoreTextFontDatabase: Remove number type asserts.

On iOS 8, the value 0 is returned as a kCFNumberIntType.
The code still works - CFNumberGetValue converts it
to a 0.0 double.

Change-Id: Ic50900b22e4fa19ad1481e8e0e293559bbfd8cd2
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>