SceneJS_math_negateMat4 = function(m, dest) {
    if (!dest) {
        dest = m;
    }

    dest[0] = -m[0];
    dest[1] = -m[1];
    dest[2] = -m[2];
    dest[3] = -m[3];
    dest[4] = -m[4];
    dest[5] = -m[5];
    dest[6] = -m[6];
    dest[7] = -m[7];
    dest[8] = -m[8];
    dest[9] = -m[9];
    dest[10] = -m[10];
    dest[11] = -m[11];
    dest[12] = -m[12];
    dest[13] = -m[13];
    dest[14] = -m[14];
    dest[15] = -m[15];

    return dest;
}
@param m mat4
@param dest mat4 - optional destination
@return {mat4} dest if specified, m otherwise
@private