Move-enable QSignalBlocker

When QSignalBlocker was reviewed, move semantics were asked for.
This patch add them.

This makes QSignalBlocker usable as a by-value argument (to transfer
control of signal blocking into a function) as well as as a return
value (to transfer control of signal blocking out of a function).

Change-Id: I714aa2a283bb33dba76e860649e88ed202e913c5
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
tst_QObject: separate QSignalBlocker tests

tst_QObject is getting big, so make a separate test for QSignalBlocker,
but leave parts of signalsBlocked() in tst_QObject as that seemed to
have been the only check for blockSignals(true) actually blocking signal
emission.

Change-Id: I1cfac035e0e39203eea8626d43f316cc6244ee86
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
qmake vcxproj: Provide saner defaults for certain WinRT options

The default values for PCH, the -ZW switch, and CharacterSet aren't
ideal for WinRT projects, so adjust these accordingly.

Task-number: QTBUG-35328
Change-Id: I78021d0785fa84e15b1f17264daa599a9418f92e
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@digia.com>
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>