* All modules are replaced with the JUCE 4.2.1 ones;
* Introjucer was replaced by Projucer;
* Also some appropriate needed fixes for Makefile.plugins;
* Removed -fvisibility=hidden flag for Linux building.

Include definitions of LinearSmoothedValueAtomic's template methods in its header file (required because the explicit instantiations built in to the OE application are not visible to plugins on OS X)

* Implemented LinearSmoothedValueAtomic class based on the
  JUCE 4.0 library' LinearSmoothedValue class but with some improvements
  that were suggested by Timur Doumler during his JUCE Summit 2015
  talk.
* LinearSmoothedValueAtomic is very convenient to use with float values
  that need linearly smoothed behaviour (like volume, etc.) and which
  are shared between several threads (i.e. audio and GUI).
* This class guarantees we won't have any race conditions and it will
  remains lock-free because of using std::atomic inside it.