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-ios/Shaders/Shader.fsh

@@ -0,0 +1,10 @@
+//
+//  Shader.fsh
+//  imguiex
+
+varying lowp vec4 colorVarying;
+
+void main()
+{
+    gl_FragColor = colorVarying;
+}

examples/apple_example/imguiex-ios/Shaders/Shader.vsh

@@ -0,0 +1,25 @@
+//
+//  Shader.vsh
+//  imguiex
+
+attribute vec4 position;
+attribute vec3 normal;
+
+varying lowp vec4 colorVarying;
+
+uniform vec3 diffuseColor;
+uniform mat4 modelViewProjectionMatrix;
+uniform mat3 normalMatrix;
+
+void main()
+{
+    vec3 eyeNormal = normalize(normalMatrix * normal);
+    vec3 lightPosition = vec3(0.0, 0.0, 1.0);
+    
+    float nDotVP = max(0.0, dot(eyeNormal, normalize(lightPosition)));
+    
+    vec3 colorLit = diffuseColor * nDotVP;
+    colorVarying = vec4( colorLit.x, colorLit.y, colorLit.z, 1.0 );
+    
+    gl_Position = modelViewProjectionMatrix * position;
+}