Added Xcode project for OpenEphysHDF5Lib, which builds a shared library (libOpenEphysHDF5.dylib) and installs it in open-ephys.app/Contents/Frameworks.  On macOS, the KWIKFormat plugin now links against libOpenEphysHDF5.dylib.

Added Xcode config files for building dylib's that are embedded in open-ephys.app/Contents/Frameworks

addresses #74

* 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.

* Updated images for collapse/show button;
* Updated animations;
* Some other small UI improvements;
* Added possibility to collapse element by clicking "ESC" key
  either on the component itself or on the TextEditor.

* Created SlicerChannelSelectorComponent class which holds inside
  all ChannelSelector's parser related components and which
  takes responsibility for parsing selected range, etc.
* Added possibility to collapse parser related components.
* Added animations.
* UI improvements.
* Minor bugs fixes.

followed instructions by Christopher Stawarz in
https://open-ephys.atlassian.net/wiki/display/OEW/Plugin+build+files

Set MACOSX_DEPLOYMENT_TARGET (i.e. the minimum supported OS X version) to 10.9.  Pass -Wpartial-availability to the compiler so it will warn about usage of API's that aren't available on all supported OS X versions.  Removed /opt/local and /usr/local from OS X header and library search paths, as they're used only by specific plugins and not needed generally.