add some composites

Ejecta misses some globalCompositeOperation : 'destination-in', 'destination-atop', 'source-in', 'source-out', 'copy'.

This pull request tries to add these composites. the core code follows : 
```
    [kEJCompositeOperationDestinationIn] = {GL_ZERO, GL_SRC_ALPHA, 1},
    [kEJCompositeOperationSourceIn] = {GL_DST_ALPHA, GL_ZERO, 1},
    [kEJCompositeOperationSourceOut] = {GL_ONE_MINUS_DST_ALPHA,GL_ZERO,1},
    [kEJCompositeOperationDestinationAtop] = {GL_ONE_MINUS_DST_ALPHA, GL_SRC_ALPHA, 1},
    [kEJCompositeOperationCopy] = {GL_ONE,GL_ZERO,1}
```