remove trialing blanks

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
use AppContext to manage all the objects excpet NativeApp

AppContext is used as centralized class to manage other objects,
except NativeApp. The implementation of NativeApp can refer other
objects by first getAppContext().

Other trivial change like singleton template class

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
SceneManager and RenderManager singleton implementation

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
slightly modify the mainLoop logic

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
change drawScene interface to accomodate multiple scene in the future

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
ready to draw node

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
node traversal interface accepts scene as first argument

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
Shader and Program class skeleton

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
change ndk toolchain to 4.8

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
move to gles3

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
initial gles, commit 1

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>
enable gles3 context

Signed-off-by: Wayne Wolf <wayne.ron.wu at gmail>