fix macOS build (following Projucer changes made in Windows, which removed /Applications/JUCE/modules from its headers). move JUCE headers under source control, so that Windows and macOS can both build against same version of JUCE. remove AUv3 target (I think it's an iOS thing, so it will never work with this macOS fluidsynth dylib).

modules/juce_gui_basics/keyboard/juce_KeyboardFocusTraverser.h

@@ -0,0 +1,91 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE library.
+   Copyright (c) 2017 - ROLI Ltd.
+
+   JUCE is an open source library subject to commercial or open-source
+   licensing.
+
+   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
+   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
+   27th April 2017).
+
+   End User License Agreement: www.juce.com/juce-5-licence
+   Privacy Policy: www.juce.com/juce-5-privacy-policy
+
+   Or: You may also use this code under the terms of the GPL v3 (see
+   www.gnu.org/licenses).
+
+   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+namespace juce
+{
+
+//==============================================================================
+/**
+    Controls the order in which focus moves between components.
+
+    The default algorithm used by this class to work out the order of traversal
+    is as follows:
+    - if two components both have an explicit focus order specified, then the
+      one with the lowest number comes first (see the Component::setExplicitFocusOrder()
+      method).
+    - any component with an explicit focus order greater than 0 comes before ones
+      that don't have an order specified.
+    - any unspecified components are traversed in a left-to-right, then top-to-bottom
+      order.
+
+    If you need traversal in a more customised way, you can create a subclass
+    of KeyboardFocusTraverser that uses your own algorithm, and use
+    Component::createFocusTraverser() to create it.
+
+    @see Component::setExplicitFocusOrder, Component::createFocusTraverser
+
+    @tags{GUI}
+*/
+class JUCE_API  KeyboardFocusTraverser
+{
+public:
+    KeyboardFocusTraverser();
+
+    /** Destructor. */
+    virtual ~KeyboardFocusTraverser();
+
+    /** Returns the component that should be given focus after the specified one
+        when moving "forwards".
+
+        The default implementation will return the next component which is to the
+        right of or below this one.
+
+        This may return nullptr if there's no suitable candidate.
+    */
+    virtual Component* getNextComponent (Component* current);
+
+    /** Returns the component that should be given focus after the specified one
+        when moving "backwards".
+
+        The default implementation will return the next component which is to the
+        left of or above this one.
+
+        This may return nullptr if there's no suitable candidate.
+    */
+    virtual Component* getPreviousComponent (Component* current);
+
+    /** Returns the component that should receive focus be default within the given
+        parent component.
+
+        The default implementation will just return the foremost child component that
+        wants focus.
+
+        This may return nullptr if there's no suitable candidate.
+    */
+    virtual Component* getDefaultComponent (Component* parentComponent);
+};
+
+} // namespace juce