Add lesson 4 codes
	new file:   .idea/ant.xml
	modified:   AndroidManifest.xml
	new file:   res/drawable-nodpi/bumpy_bricks_public_domain.jpg
	new file:   res/raw/per_pixel_fragment_shader.glsl
	new file:   res/raw/per_pixel_vertex_shader.glsl
	new file:   res/raw/point_fragment_shader.glsl
	new file:   res/raw/point_vertex_shader.glsl
	modified:   res/values/strings.xml
	new file:   src/com/teok/android/opengles/common/RawResourceReader.java
	new file:   src/com/teok/android/opengles/common/ShaderHelper.java
	new file:   src/com/teok/android/opengles/common/TextureHelper.java
	new file:   src/com/teok/android/opengles/lesson4/LessonFourActivity.java
	new file:   src/com/teok/android/opengles/lesson4/LessonFourRenderer.java