Silence warnings about not supporting setMask on platforms like eglfs

Showing warnings based on an (otherwise unused) WindowMasks platform capability
is wrong. The default implementation of setMask() shows a warning anyway so it
is safe to call it in any case.

On top of this, platforms like eglfs may want to avoid showing any warnings,
since they  are completely useless for end users and pollute their debug
output and Creator panes. The standard way is to provide an empty implementation
for the function. This cannot work however if there are hardcoded warnings
generated in the common widget code.

Change-Id: I842a96b5b84c50b7caa59bdd48107785b21ab5af
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>
Fix inconsistent export in QPixmapIconEngine

Removes "warning C4273: 'operator <<' : inconsistent dll linkage" under
MSVC2013.

Change-Id: I463441802a76f02db329631947232c70a85ae9e7
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Accessibility: improve text attribute ranges

Improve consistency and use QTextDocument functions to find ranges
instead of coming up with our own scheme. This is important since
QCursor's char format depends on block positions.

Change-Id: I94eb137882dc6b5f7b01fa7693b4a536cc48d02a
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>