Previously, all parameter changes were routed first into
cachedParamValues. Then, on each audio callback, an update would be sent
to the editor via the parameterDispatcher for each changed value in
cachedParamValues.

Now, parameter changes are immediately added to the parameterDispatcher,
without needing to wait for an audio callback.

In Windows DLL builds we inject operator new/delete definitions into
classes with a leak detector. This requires that all inheritance from
such classes must be public, and classes inheriting from multiple such
classes must disambiguate between the base's operators.

Fixing a regression introduced in da38c1ed.

Before this commit an already started timer would wait until the
previously set tick time before applying the new one. This problem seems
to have affected the Windows implementation only.

The issue affected projects not depending on juce_audio_devices.

Prior to this fix a data race could occur on 
ARAAudioSourceReader::hostReader between the functions 
didEnableAudioSourceSamplesAccess() and readSamples().

Previously, whenever the output device sample time changed from
'invalid' to 'valid', the AudioBuffer fifo in the AudioIODeviceCombiner
was cleared. This caused a data race, since the clear operation was not
mutually exclusive with writes from the input device.

This change causes the AudioIODeviceCombiner to keep track of the
timestamp of the first input device callback after the output device is
invalidated. The output device is unable to read from the fifo until its
timestamp exceeds the stored input device callback timestamp.

Previously, we would allocate storage large enough to fit the entire
contents of the input stream, even if this was lower than the
maxNumBytesToWrite.