Bugfix: Errors while building v8gl

I was getting this error while running `./setup.sh`:

```bash
- - - Building v8gl (x64.release) - - -

cd src/ && xxd -i "js/console.js" "js/console.h"
cd src/ && xxd -i "js/interval.js" "js/interval.h"
cd src/ && xxd -i "js/timeout.js" "js/timeout.h"
rm -rf ./out/x64.release
mkdir -p ./out/x64.release
g++ -Wall -D__V8GL__ -D__WEBGL__ -I../external/libpng/include -I../external/v8/include src/main.cpp src/v8gl.cpp src/binding/gl.cpp src/binding/webgl.cpp src/binding/glu.cpp src/binding/glut.cpp src/lib/fs.cpp src/lib/os.cpp src/api/arraybuffer.cpp src/api/navigator.cpp src/api/script.cpp src/api/text.cpp src/api/texture.cpp -o ./out/x64.release/v8gl lib/x64/libpng.a lib/x64/libv8_base.a lib/x64/libv8_nosnapshot.a -lpthread -lz -lm -lglut -lGLU -lGL
g++: error: lib/x64/libpng.a: No such file or directory
g++: error: lib/x64/libv8_base.a: No such file or directory
g++: error: lib/x64/libv8_nosnapshot.a: No such file or directory
make: *** [x64.release] Error 1
Done.


- - - Setting up adk (x64.release) - - -

cp: cannot stat `/home/smotko/libs/lycheeJS-adk/v8gl/out/x64.release/v8gl': No such file or directory
Done.
```

The fix copies the contents of libpng and v8 out folders to v8gl/lib/x64 - it's probably not an optimal solution for this issue, but it works for me.

In the second commit I've added the necessary `./setup.sh` step to the README file. I hope you don't mind.

Cheers