Imported the root directory tree.
added: common source files
added: source and project files of PostProcessEffectTest
added: the template for app directory
copied: app template to PostProcessEffectTest
added: resource files of PostProcessEffectTest
updated: PostProcessEffectTest
added: TextureFontTest
copied: dll files in _Template/app to TextureFontTest/app
added: source files and project files of AsyncLoadingTest
copied: the template 'app' from _Template to AsyncLoadingTest
added: resource files of AsyncLoadingTest
  - models, textures and an HLSL effect file.
cleaned up: PostProcessEffect.hpp & cpp
updated: introduced a mechanism to let user select graphics library from Direct3D & OpenGL.
added: source and project files of GraphicsElementsTest
updated: PostProcessEffectTest.cpp
  - Replaced some D3D-specific code with graphics library independent APIs.
updated: TestMain_Win32.cpp
  - Uses built-in font.
  - etc.
updated: Graphics/AsyncLoadingTest
updated: PostProcessEffectTest
updated: HDRPostProcessor.fx
- Added a technique: AdaptedLuminanceDisplay.
- Added a pixel shader: AdaptedLuminanceDisplayPS.