Pull request #907 addressed a specific case where a signal was emitted before a state update.
If an application's slot then calls back into the instance, the instance was in an inconsistent
state. This commit audits and fixes similar issues throughout the pyqtgraph library. This
commit fixes several latent issues:
* SignalProxy: flush -> sigDelayed -> signalReceived would have incorrectly resulted in timer.stop().
* ViewBox: resizeEvent -> sigStateChange -> background state
* ViewBox: setRange -> sigStateChange -> autoranging not updated correctly
* ViewBox: updateMatrix -> sigTransformChanged -> any _matrixNeedsUpdate = True -> ignored
* Parameter: Child may have missed state tree messages on insert or received extra on remove
* GraphicsView: updateMatrix -> sigDeviceRangeChanged/sigDeviceTransformChange -> before propagated to locked viewports.
