* Added feature to create plugins using VisualizerEditors;
* It's possible to manipulate with GUI content both of GenericEditor's
  plugin component and Visualizer canvas (in the tab or window);
* Created file templates for VisualizerEditor and Visualizer (Canvas);
* VisualizerEditor class minor improvements;
* Other minor improvements;
* Refactoring and stylystic fixes.

* Created 3rd slider-page on creating project steps which is used
  to select appropriate plugin, processor type, plugin GUI template,
  other options.
* Created plugin GUI templates system;
* Created some plugin GUI templates for GenericEditor;
* ButtonGroupManager and TiledButtonGroupManager classes minor
  improvements and fixes;
* Changed index of ProcessorType::UtilityProcessor;
* Other minor bugs fixes.

* Added template for creating appropriate JUCE GUI component which will
  be automatically created inside plugin editor.
* Some improvements to the editor plugin template due to the addition
  of GUI component inside it.
* Added possibility to change desired with of the plugin in the config.
* Some minor improvements.
* Some stylystic fixes.

It was in the private section. Still is practically...
Motivation:
Whenever an editor is closed, it destroy it's DataViewport tab (if it exists)
I don't want my "shared" tab to be closed when any one editor is closed, and I can fool the
VisualizerEditor destructor now.

Implemented @sept-en's tip.
VisualizerEditor implements the listener class, with a dummy windowClosed() method.
Derivations of VisualizerEditor can optionally implement windowClosed().

This might be very Cyclops Stimulator specific addition, and there might be a better way to do this:
DataWindow is used only by VisulaizerEditors. So I added a callback to the editor whenever an (open) DataWindow is closed.
I don't know how useful this might be for plugins other than for Cyclops.

Motivation: Since the datawindow is also shared by CyclopsEditors, when a window is closed, only the editor which created the window would get it's windowSelector button toggled back to "off".

With this PR, the button toggles, and the editor's windowClosed callback is called, in which the message is passed to peers through an internally maintained structure -- so that they can toggle their buttons too.

These changes were made to primarily to accommodate for the cyclops-stimulator. Since buttonClicked manipulates the DataViewport via AccessClass, a sub-class of VisualizerEditor cannot functionally override the method.
Hence:

* Added protected methods which manipulate DataViewport (via AccessClass)
* moved the SelectorButtons into protected area, essential!
* All of the additions are essential to the cyclops-stimulator.
* There is NO change in the public interface.

Now, my buttonClicked method can access the SelectorButtons, manipulate (anything about!!) DataViewport.
Please remove the (new) comments from VisualizerEditor::buttonClicked (.cpp), they are not needed anymore.

* Added docs for the class. Override only buttonEvent (as for other non-visual editors)
* Started fixing other editors, a lot of redundant code can be removed.
* See comments in VisualEditor.cpp

Refactoring.

* Appropriate dependencies also have been changed.

* 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.

* Removed ChannelSelectorRegion class and appropriate instances
  since now it's redundant.

* Now ChannelSelector class contains three instances
  of TiledButtonGroupManager class (AUDIO, RECORD, PARAM).
  This managers own appropriate buttons, position it, responsible
  for all animations, fuzzy selection via dragging mouse, etc.
* Button group managers minor fixes.

* Added custom audio processor editor for CAR plugin - CAREditor;
* Added buttons to switch between "Reference" and "Affected" channels;
* CAR processor some minor changes;
* Some minor changes in GenericEditor class which provide more
  possibilities for plugins (e.g. plugins can implement their own
  resized() methods, etc.);
* Added UIUtilities header file in which we can include any
  UI components/utilities which will be useful for easier plugin
  creation.

* Since "Small text" renders very bad, without any hinting, we replace
  it by "Default" font.  And also "Default" font is much more suitable
  for Material Design.
* Adjusted font sizes.