Performance improvements to vector push/pop front/back:

Before:

    Vector::popBack x 50000: 0.31696200370789s
    Vector::popFront x 1000: 0.33041715621948s
    Vector::pushBack x 50000: 0.61939287185669s
    Vector::pushFront x 50000: <Too damn long.>

After:

    Vector::popBack x 50000: 0.2187979221344s
    Vector::popFront x 1000: 0.35270094871521s
    Vector::pushBack x 50000: 0.2260570526123s
    Vector::pushFront x 50000: 0.24150896072388s