- macOS behaviour of setRealtime now matches other platforms

MR feedback

- added unit tests
- best performance timers used for each platform
- fixed an issue in which timer callbacks could drift

This commit adds fixes for generating unique hardware IDs on Windows. The SMBIOS is parsed to generate a unique ID based on hardware factors of the local machine.

This commit adds the JUCE_DECLARE_SCOPED_ENUM_BITWISE_OPERATORS macro, enabling bitwise operators on scoped enums. This feature simplifies the use of scoped enums in situations where bitwise operations are needed.

Android devices won't necessarily be able to load MP3 files, so that
option has been removed from the file chooser. FLAC files should be
supported, but were missing from the MIME table.

The demo no longer tries to load files into the thumbnail view if they
previously failed to load into the transport.

This allows paths that are prefixed with environment variables to behave
as expected. This is useful when scanning the default LV2 locations in
the AudioPluginHost on Windows.

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.

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.

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

Previously, JUCE_ANDROID_REALTIME_THREAD_AVAILABLE sometimes remained
unset, even though JUCE_USE_ANDROID_OBOE was set to its default value.
This is because in this case, JUCE_USE_ANDROID_OBOE is only defined in
juce_audio_basics.h, so it is not visible when compiling juce_core.cpp.