Add the default argument for the new connection syntax

Task-number: QTBUG-36549
Change-Id: I3addacf4b0698df91960f7b8e9c2ed93e935f848
Reviewed-by: Branislav Katreniak <katreniak@gmail.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
CMake: don't require GL when build with -no-opengl

Task-number: QTBUG-36509
Change-Id: I03451527ab91754d87ff2a43985952c7c7641826
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Fix QByteArray documentation w.r.t. QString-related methods

There's no loss of data when converting a Unicode string to UTF-8,
so don't state that in the docs.

Change-Id: If26914ec674a994d9c59136448e8e4292d0412e8
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>