Make OpenGL texture glyph cache use the right freetype glyphs

The freetype font engine would fall back to rasterizing glyphs
via QPainterPath in QFontEngine::alphaMapForGlyph() which has
a rather unfortunate implementation.

Change-Id: Ic0b4095b6f17ab33f0602139f0a8fb441dfba0ee
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Add note about fullscreen on Android to changes-5.2.0

Task-number: QTBUG-33135
Change-Id: I49c74fee0da738768a20735c4aac904f40322298
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Doc: Updated url variable in qdocconf files.

In 5.2, the HTML output is in a flatter structure and when they are
hosted in qt-project.org/doc, the documentation will be found at
http://qt-project.org/doc/qt-$QT_VER

The url variable is used by projects outside of Qt 5 which need
to link to Qt 5 documentation, such as Qt Creator.

Task-number: QTBUG-34584
Change-Id: Ifa55fcd9e402b0e184a41e316340e46aeb7101de
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
Android: prevent main activity to be recreated.

Add more config changes needed for API 13+
API 13+ is mandatory to build any Qt for Android application.

Change-Id: I595f7174dd2fc8a0865772f9780ce606e1f1fcf1
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Revert "Use Qt's own glyph cache with the freetype engine."

This reverts commit 8c58640fdfe5d182cd8ab9ad0598c54c0487eb7c.

The intent was to reduce the maintenance of parallel code paths,
but this had a negative impact on performance so we need to
enable it again.

Change-Id: Ic58f7781ff076055e7c48f20fc0e7a8a2c9e51a4
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>