remove last traces of copybit

#include <GLES/gl.h>

#include <GLES/glext.h>

struct android_native_buffer_t;

namespace android {

    void (*renderTriangle)(GL, vertex_t*, vertex_t*, vertex_t*);

};

struct copybits_context_t {

    // A handle to the blit engine, if it exists, else NULL.

    int32_t                 minScale;

    int32_t                 maxScale;

    android_native_buffer_t* drawSurfaceBuffer;

};

struct ogles_context_t {

    context_t               rasterizer;

    array_machine_t         arrays         __attribute__((aligned(32)));

    EGLSurfaceManager*      surfaceManager;

    EGLBufferObjectManager* bufferObjectManager;

    // copybits is only used if LIBAGL_USE_GRALLOC_COPYBITS is

    // defined, but it is always present because ogles_context_t is a public

    // struct that is used by clients of libagl. We want the size and offsets

    // to stay the same, whether or not LIBAGL_USE_GRALLOC_COPYBITS is defined.

    copybits_context_t      copybits;

    GLenum                  error;

    static inline ogles_context_t* get() {