More maths differences 
Contrast the following cart in pico8 and picolove

http://www.lexaloffle.com/bbs/?tid=2464

![14153 p8](https://cloud.githubusercontent.com/assets/49612/9864426/69098b06-5b41-11e5-843f-1381ba2ee0d8.png)

It's set to tween using `ease_in_out_cubic`which gets great results in pico8, but bad results in picolove. Other easing functions are also affected. 

``` lua
function ease_in_out_cubic(t,b,c,d)  -- cubic easing in/out - acceleration until halfway, then deceleration
  t /= d/2
  if (t < 1) return c/2*t*t*t + b
  t -= 2
  return c/2*(t*t*t + 2) + b
end
```

I've ruled out short operators by manually expanding them. No difference.

Perhaps an issue with expression parsing?
