Remove local glfw3 lib for osx. (+1 squashed commit)

Squashed commits:
[34cc3b7] Adds osx example. (+6 squashed commits)
Squashed commits:
[20330f2] Uses glfw by brew install.
[0427861] Renames imguiex folder name to imguiex-ios
[f9e27e5] Renames ios_example to apple_example.
[44f8fe3] Updates the glfw header/library path.
[919f279] Renames target from imguiex to imguiex-ios since there is already a imguiex-osx target now.
[24395f5] Adds osx example.

examples/apple_example/imguiex-osx/main.m

@@ -0,0 +1,13 @@
+//
+//  main.m
+//  imguiex-osx
+//
+//  Created by James Chen on 4/5/16.
+//  Copyright © 2016 Joel Davis. All rights reserved.
+//
+
+#import <Cocoa/Cocoa.h>
+
+int main(int argc, const char * argv[]) {
+    return NSApplicationMain(argc, argv);
+}