iOS: Make sure we're deleting framebuffers in the right context

When a QWindow was destroyed, we'd delete its corresponding buffers,
but failed to make the correct EAGLContext current first. This would
result in deleting/invalidating buffers for another window (whatever
window's context was current at the time), and that window would then
seemingly stop rendering anything, and turn black on rotation.

Task-number: QTBUG-32246
Change-Id: I335a8c580203fc01e43da31c5cb6f567614c26fc
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
MANIFEST:NO is not written to vcproj

When defining QMAKE_LFLAGS += /MANIFEST:NO to pro file,
it is not written to vcproj in VS2008.
Added MANIFEST:NO generation to vcproj

Task-number: QTBUG-31975

Change-Id: I5f84b30db711bf9c317ca20dc65b207140edb398
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
make requirement for -private suffix explicit, take 2

the previous attempt broke ActiveQt, as it actually has public modules
without headers (they are provided by a common base module).
so explicitly mark the internal modules as such instead of applying
heuristics.

Change-Id: I8d8a2ee66f02c3444da2036a497e7f382f089f62
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>