Merge branch '4.7' of scm.dev.nokia.troll.no:qt/oslo-staging-2 into 4.7-integration

* '4.7' of scm.dev.nokia.troll.no:qt/oslo-staging-2:
  Removed a Valgrind warning.
  Made QGLExtensions::glExtensions() thread-safe.
  QTreeView: Optimise QTreeViewPrivate::viewIndex
  Optimize QSortFilterProxyModel
  QTreeView: speedup more QTreeViewPrivate::layout(-1)
  Remove debug output from qt_eglproperties_set_glformat
  Delete the QGLContext in ~QX11GLPixmapData
  Made QGLTextureCache::instance() threadsafe.
  Add support for QFont::NoAntialias on QWS
  Fix 1-bit to 8-bit conversion for bitmap fonts on QWS