move Mesh in separate files

Signed-off-by: Wayne Wolf <wayne.ron.wu@googlemail>
move material to separate files

Signed-off-by: Wayne Wolf <wayne.ron.wu@googlemail>
move Camera to separate files

Signed-off-by: Wayne Wolf <wayne.ron.wu@googlemail>
move light to separate files

Signed-off-by: Wayne Wolf <wayne.ron.wu@googlemail>