changed enemy bullet effects
Merge branch 'master' of https://github.com/Wu-Hao/Moon3D
made enemy bullet prettier
value adjustments
Merge pull request #20 from natural-law/master

Add MeshCache to cache the mesh objects.
Solve the problem when game go to background/foreground on android.
Merge branch 'master' of https://github.com/Wu-Hao/Moon3D